C# – Developer stories

Task with parameters in C#

Async Task with Parameters

The following quick example shows how you can run a Task with argument.

 await Task.Run(()=>  Db.Session.Insert(Globals.CurrentSession));
 await Task.Run(Globals.ModelViews.AccountsToList);

How to update Listview from Background Worker in WinForm-C#.Net ?

How to solve ‘Cross-thread operation not valid: error in C# Background Worker

C# WinForm provides Background Worker Control that is capable of run asynchronous job in background. This must be ideal for fetching data in the background .

What about updating UI from background ? Like update a listview items from database . Let’s begin from setup.

How to ?

The Background Worker control has a event ,DoWork where we can add our background tasks.

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) 
{
// logic here         
}

We can use the RunWorkerCompleted to apply logic which will executed after completion.

In the form load event (or from any event ) you can start the task by running

   this.backgroundWorker1.RunWorkerAsync();

Problem with UI and Worker

When you try to access a component in the UI from a Background Worker DoWork event, may end up like this.

System.InvalidOperationException: ‘Cross-thread operation not valid: Control ‘listView1’ accessed from a thread other than the thread it was created on…

Solution

To bypass this error C#.Net provides invoke method which execute the delegate specified.

To add items to the listview from a background worker I used the following code snippet which uses a MethodInvoker and a delegate

        try
            {
listView1.Invoke(new MethodInvoker(
                                 delegate
                                 {
                                     item = new ListViewItem("");
                                     item.SubItems.Add(new ListViewItem.ListViewSubItem(item, "Some Column Value Here"));                                       
                                     listView1.Items.Add(item);
                                 }
                                 ));               
           }
            catch (Exception)
            {
                throw;
            }

I hope this will help you and recommend the following snippets.

C# : Auto create folder

Auto create folder in C#

Function for auto create folder in C#

	using System.IO;
	public static void AutoCreateDirectory(string dpath)
	{
	try
	{
	if (!Directory.Exists(dpath))
	{
	Directory.CreateDirectory(dpath);
	}
	}
	catch (Exception ee)
	{

	MessageBox.Show(ee.Message.ToString());
	}

	}

view raw autocreate_dir.cs hosted with ❤ by GitHub

C#: ViewModelBase class

ViewModelBase class which implements INotifyPropertyChanged in C#

C# WPF – An Observable String Dictionary class, which can be useful for storing and binding values as (key, value) pairViewModelBase class which implements INotifyPropertyChanged in C# WPF .

An Observable String Dictionary class, which can be useful for storing and binding values as key, value pairs

	public abstract class ViewModelBase : INotifyPropertyChanged
	{
	/// <summary>
	/// Multicast event for property change notifications.
	/// </summary>
	public event PropertyChangedEventHandler PropertyChanged;

	/// <summary>
	/// Checks if a property already matches a desired value. Sets the property and
	/// notifies listeners only when necessary.
	/// </summary>
	/// <typeparam name="T">Type of the property.</typeparam>
	/// <param name="storage">Reference to a property with both getter and setter.</param>
	/// <param name="value">Desired value for the property.</param>
	/// <param name="propertyName">Name of the property used to notify listeners.This
	/// value is optional and can be provided automatically when invoked from compilers that
	/// support CallerMemberName.</param>
	/// <returns>True if the value was changed, false if the existing value matched the
	/// desired value.</returns>
	protected virtual bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = null)
	{
	if (object.Equals(storage, value)) return false;
	storage = value;
	// Log.DebugFormat("{0}.{1} = {2}", this.GetType().Name, propertyName, storage);
	this.OnPropertyChanged(propertyName);
	return true;
	}

	/// <summary>
	/// Notifies listeners that a property value has changed.
	/// </summary>
	/// <param name="propertyName">Name of the property used to notify listeners. This
	/// value is optional and can be provided automatically when invoked from compilers
	/// that support <see cref="CallerMemberNameAttribute"/>.</param>
	protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
	{
	var eventHandler = this.PropertyChanged;
	if (eventHandler != null)
	eventHandler(this, new PropertyChangedEventArgs(propertyName));
	}
	}

view raw ViewModelBase.cs hosted with ❤ by GitHub

On GitHub , All Gits

C#: Observable Dictionary

C# WPF – An Observable String Dictionary class

C# WPF – An Observable String Dictionary class, which can be useful for storing and binding values as (key, value) pair

	// The orginal class was obtained from official site, then I made some desirable changes such as `UpdateOrAdd`,
	// which I think usefull for others
	//
	using System;
	using System.Collections;
	using System.Collections.Generic;
	using System.ComponentModel;

	namespace mynamespace
	{

	class ObservableDictionary : IDictionary<string, string>, INotifyPropertyChanged
	{
	//------------------------------------------------------
	//
	// Constructors
	//
	//------------------------------------------------------

	#region Constructors

	/// <summary>
	/// Creates a ContentLocatorPart with the specified type name and namespace.
	/// </summary>
	public ObservableDictionary()
	{
	_nameValues = new Dictionary<string, string>();
	}

	#endregion Constructors

	//------------------------------------------------------
	//
	// Public Methods
	//
	//------------------------------------------------------

	#region Public Methods

	/// <summary>
	/// Adds a key/value pair to the ContentLocatorPart. If a value for the key already
	/// exists, the old value is overwritten by the new value.
	/// </summary>
	/// <param name="key">key</param>
	/// <param name="val">value</param>
	/// <exception cref="ArgumentNullException">key or val is null</exception>
	/// <exception cref="ArgumentException">a value for key is already present in the locator part</exception>
	public void Add(string key, string val)
	{
	if (key == null \|\| val == null)
	{
	throw new ArgumentNullException(key == null ? "key" : "val");
	}
	_nameValues.Add(key, val);
	FireDictionaryChanged();
	}

	/// <summary>
	/// Removes all name/value pairs from the ContentLocatorPart.
	/// </summary>
	public void Clear()
	{
	int count = _nameValues.Count;

	if (count > 0)
	{
	_nameValues.Clear();

	// Only fire changed event if the dictionary actually changed
	FireDictionaryChanged();
	}
	}

	public void UpdateOrAdd(string key,string value)
	{
	if (ContainsKey(key) == false)
	{
	Add(key, value);
	}
	else
	{
	Remove(key);
	Add(key, value);
	}
	}

	/// <summary>
	/// Returns whether or not a value of the key exists in this ContentLocatorPart.
	/// </summary>
	/// <param name="key">the key to check for</param>
	/// <returns>true - yes, false - no</returns>
	public bool ContainsKey(string key)
	{
	return _nameValues.ContainsKey(key);
	}

	/// <summary>
	/// Removes the key and its value from the ContentLocatorPart.
	/// </summary>
	/// <param name="key">key to be removed</param>
	/// <returns>true - the key was found in the ContentLocatorPart, false o- it wasn't</returns>
	public bool Remove(string key)
	{
	bool exists = _nameValues.Remove(key);

	// Only fire changed event if the key was actually removed
	if (exists)
	{
	FireDictionaryChanged();
	}

	return exists;
	}

	/// <summary>
	/// Returns an enumerator for the key/value pairs in this ContentLocatorPart.
	/// </summary>
	/// <returns>an enumerator for the key/value pairs; never returns null</returns>
	IEnumerator IEnumerable.GetEnumerator()
	{
	return _nameValues.GetEnumerator();
	}

	/// <summary>
	/// Returns an enumerator forthe key/value pairs in this ContentLocatorPart.
	/// </summary>
	/// <returns>an enumerator for the key/value pairs; never returns null</returns>
	public IEnumerator<KeyValuePair<string, string>> GetEnumerator()
	{
	return ((IEnumerable<KeyValuePair<string, string>>)_nameValues).GetEnumerator();
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="key"></param>
	/// <param name="value"></param>
	/// <returns></returns>
	/// <exception cref="ArgumentNullException">key is null</exception>
	public bool TryGetValue(string key, out string value)
	{
	if (key == null)
	throw new ArgumentNullException("key");

	return _nameValues.TryGetValue(key, out value);
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="pair"></param>
	/// <exception cref="ArgumentNullException">pair is null</exception>
	void ICollection<KeyValuePair<string, string>>.Add(KeyValuePair<string, string> pair)
	{
	((ICollection<KeyValuePair<string, string>>)_nameValues).Add(pair);
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="pair"></param>
	/// <returns></returns>
	/// <exception cref="ArgumentNullException">pair is null</exception>
	bool ICollection<KeyValuePair<string, string>>.Contains(KeyValuePair<string, string> pair)
	{
	return ((ICollection<KeyValuePair<string, string>>)_nameValues).Contains(pair);
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="pair"></param>
	/// <returns></returns>
	/// <exception cref="ArgumentNullException">pair is null</exception>
	bool ICollection<KeyValuePair<string, string>>.Remove(KeyValuePair<string, string> pair)
	{
	return ((ICollection<KeyValuePair<string, string>>)_nameValues).Remove(pair);
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="target"></param>
	/// <param name="startIndex"></param>
	/// <exception cref="ArgumentNullException">target is null</exception>
	/// <exception cref="ArgumentOutOfRangeException">startIndex is less than zero or greater than the lenght of target</exception>
	void ICollection<KeyValuePair<string, string>>.CopyTo(KeyValuePair<string, string>[] target, int startIndex)
	{
	if (target == null)
	throw new ArgumentNullException("target");
	if (startIndex < 0 \|\| startIndex > target.Length)
	throw new ArgumentOutOfRangeException("startIndex");

	((ICollection<KeyValuePair<string, string>>)_nameValues).CopyTo(target, startIndex);
	}

	#endregion Public Methods

	//------------------------------------------------------
	//
	// Public Operators
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Public Events
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Public Properties
	//
	//------------------------------------------------------

	#region Public Properties

	/// <summary>
	/// The number of name/value pairs in this ContentLocatorPart.
	/// </summary>
	/// <value>count of name/value pairs</value>
	public int Count
	{
	get
	{
	return _nameValues.Count;
	}
	}

	/// <summary>
	/// Indexer provides lookup of values by key. Gets or sets the value
	/// in the ContentLocatorPart for the specified key. If the key does not exist
	/// in the ContentLocatorPart,
	/// </summary>
	/// <param name="key">key</param>
	/// <returns>the value stored in this locator part for key</returns>
	public string this[string key]
	{
	get
	{
	if (key == null)
	{
	throw new ArgumentNullException("key");
	}

	string value = null;
	_nameValues.TryGetValue(key, out value);
	return value;
	}
	set
	{
	if (key == null)
	{
	throw new ArgumentNullException("key");
	}

	if (value == null)
	{
	throw new ArgumentNullException("value");
	}

	string oldValue = null;
	_nameValues.TryGetValue(key, out oldValue);

	// If the new value is actually different, then we add it and fire
	// a change notification
	if ((oldValue == null) \|\| (oldValue != value))
	{
	_nameValues[key] = value;
	FireDictionaryChanged();
	}
	}
	}

	/// <summary>
	///
	/// </summary>
	public bool IsReadOnly
	{
	get
	{
	return false;
	}
	}

	/// <summary>
	/// Returns a collection of all the keys in this ContentLocatorPart.
	/// </summary>
	/// <value>keys</value>
	public ICollection<string> Keys
	{
	get
	{
	return _nameValues.Keys;
	}
	}

	/// <summary>
	/// Returns a collection of all the values in this ContentLocatorPart.
	/// </summary>
	/// <value>values</value>
	public ICollection<string> Values
	{
	get
	{
	return _nameValues.Values;
	}
	}

	#endregion Public Properties

	//------------------------------------------------------
	//
	// Public Events
	//
	//------------------------------------------------------

	//------------------------------------------------------
	//
	// Internal Methods
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Internal Operators
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Internal Events
	//
	//------------------------------------------------------

	#region Public Events

	/// <summary>
	///
	/// </summary>
	public event PropertyChangedEventHandler PropertyChanged;

	#endregion Public Events

	//------------------------------------------------------
	//
	// Internal Properties
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Private Methods
	//
	//------------------------------------------------------

	#region Private Methods

	/// <summary>
	/// Notify the owner this ContentLocatorPart has changed.
	/// </summary>
	private void FireDictionaryChanged()
	{
	if (PropertyChanged != null)
	{
	PropertyChanged(this, new PropertyChangedEventArgs(null));
	}
	}

	#endregion Private Methods

	//------------------------------------------------------
	//
	// Private Fields
	//
	//------------------------------------------------------

	#region Private Fields

	/// <summary>
	/// The internal data structure.
	/// </summary>
	private Dictionary<string, string> _nameValues;

	#endregion Private Fields
	}
	}

view raw observableStringDictionary.cs hosted with ❤ by GitHub

C#.Net connection string

C#.Net SQL connection string

This is a C#.Net SQL App.config connection string snippet

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <configSections>
    </configSections>
    <connectionStrings>
        <add name="Dolphin_Accounts.Properties.Settings.sql_connection"
            connectionString="Data Source=.\sqlexpress;Initial Catalog=dolphine;User ID=sa;Password=" />
    </connectionStrings>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2"/>
    </startup>
  
</configuration>

Create Checked List Box in WPF C#

Checked List box is the combination of Text and Check box. In the C# tool box you have Listbox and Combo box , not the checked listbox.

The Data template become the savior for you. We can create a Data Template for our List box.

In fact Data template can be used to customize the look and feel of the listbox items, what ever you wish.

Let’s add a Simple ListBox with Check box using XAML code which bind the Product List

<ListBox Style="{DynamicResource prent_and_groups_List}"   Background="LightGreen" SelectedItem="SlectedAccount" ItemsSource="{Binding Products}"   Grid.Row="1" Grid.Column="1"  Grid.RowSpan="2" >
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <CheckBox IsChecked="{Binding Ischecked}" Content="{Binding Name}" />
                </DataTemplate>
            </ListBox.ItemTemplate>
            
        </ListBox>

C# WPF – Custom Observable String Dictionary for Binding

Use custom Observable Dictionary for Binding in WPF C#.Net

Observable collection objects come handy when you dealing with Binding controls with values in WPF and C#.Net.

Dictionary object help you to build a collection values using a single dictionary with key, value pair.

With both we can build a custom class for binding and dynamically updated collection, which can be used for multiple purposes, around your projects.

The root : Observable Dictionary

	// The orginal class was obtained from official site, then I made some desirable changes such as `UpdateOrAdd`,
	// which I think usefull for others
	//
	using System;
	using System.Collections;
	using System.Collections.Generic;
	using System.ComponentModel;

	namespace mynamespace
	{

	class ObservableDictionary : IDictionary<string, string>, INotifyPropertyChanged
	{
	//------------------------------------------------------
	//
	// Constructors
	//
	//------------------------------------------------------

	#region Constructors

	/// <summary>
	/// Creates a ContentLocatorPart with the specified type name and namespace.
	/// </summary>
	public ObservableDictionary()
	{
	_nameValues = new Dictionary<string, string>();
	}

	#endregion Constructors

	//------------------------------------------------------
	//
	// Public Methods
	//
	//------------------------------------------------------

	#region Public Methods

	/// <summary>
	/// Adds a key/value pair to the ContentLocatorPart. If a value for the key already
	/// exists, the old value is overwritten by the new value.
	/// </summary>
	/// <param name="key">key</param>
	/// <param name="val">value</param>
	/// <exception cref="ArgumentNullException">key or val is null</exception>
	/// <exception cref="ArgumentException">a value for key is already present in the locator part</exception>
	public void Add(string key, string val)
	{
	if (key == null \|\| val == null)
	{
	throw new ArgumentNullException(key == null ? "key" : "val");
	}
	_nameValues.Add(key, val);
	FireDictionaryChanged();
	}

	/// <summary>
	/// Removes all name/value pairs from the ContentLocatorPart.
	/// </summary>
	public void Clear()
	{
	int count = _nameValues.Count;

	if (count > 0)
	{
	_nameValues.Clear();

	// Only fire changed event if the dictionary actually changed
	FireDictionaryChanged();
	}
	}

	public void UpdateOrAdd(string key,string value)
	{
	if (ContainsKey(key) == false)
	{
	Add(key, value);
	}
	else
	{
	Remove(key);
	Add(key, value);
	}
	}

	/// <summary>
	/// Returns whether or not a value of the key exists in this ContentLocatorPart.
	/// </summary>
	/// <param name="key">the key to check for</param>
	/// <returns>true - yes, false - no</returns>
	public bool ContainsKey(string key)
	{
	return _nameValues.ContainsKey(key);
	}

	/// <summary>
	/// Removes the key and its value from the ContentLocatorPart.
	/// </summary>
	/// <param name="key">key to be removed</param>
	/// <returns>true - the key was found in the ContentLocatorPart, false o- it wasn't</returns>
	public bool Remove(string key)
	{
	bool exists = _nameValues.Remove(key);

	// Only fire changed event if the key was actually removed
	if (exists)
	{
	FireDictionaryChanged();
	}

	return exists;
	}

	/// <summary>
	/// Returns an enumerator for the key/value pairs in this ContentLocatorPart.
	/// </summary>
	/// <returns>an enumerator for the key/value pairs; never returns null</returns>
	IEnumerator IEnumerable.GetEnumerator()
	{
	return _nameValues.GetEnumerator();
	}

	/// <summary>
	/// Returns an enumerator forthe key/value pairs in this ContentLocatorPart.
	/// </summary>
	/// <returns>an enumerator for the key/value pairs; never returns null</returns>
	public IEnumerator<KeyValuePair<string, string>> GetEnumerator()
	{
	return ((IEnumerable<KeyValuePair<string, string>>)_nameValues).GetEnumerator();
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="key"></param>
	/// <param name="value"></param>
	/// <returns></returns>
	/// <exception cref="ArgumentNullException">key is null</exception>
	public bool TryGetValue(string key, out string value)
	{
	if (key == null)
	throw new ArgumentNullException("key");

	return _nameValues.TryGetValue(key, out value);
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="pair"></param>
	/// <exception cref="ArgumentNullException">pair is null</exception>
	void ICollection<KeyValuePair<string, string>>.Add(KeyValuePair<string, string> pair)
	{
	((ICollection<KeyValuePair<string, string>>)_nameValues).Add(pair);
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="pair"></param>
	/// <returns></returns>
	/// <exception cref="ArgumentNullException">pair is null</exception>
	bool ICollection<KeyValuePair<string, string>>.Contains(KeyValuePair<string, string> pair)
	{
	return ((ICollection<KeyValuePair<string, string>>)_nameValues).Contains(pair);
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="pair"></param>
	/// <returns></returns>
	/// <exception cref="ArgumentNullException">pair is null</exception>
	bool ICollection<KeyValuePair<string, string>>.Remove(KeyValuePair<string, string> pair)
	{
	return ((ICollection<KeyValuePair<string, string>>)_nameValues).Remove(pair);
	}

	/// <summary>
	///
	/// </summary>
	/// <param name="target"></param>
	/// <param name="startIndex"></param>
	/// <exception cref="ArgumentNullException">target is null</exception>
	/// <exception cref="ArgumentOutOfRangeException">startIndex is less than zero or greater than the lenght of target</exception>
	void ICollection<KeyValuePair<string, string>>.CopyTo(KeyValuePair<string, string>[] target, int startIndex)
	{
	if (target == null)
	throw new ArgumentNullException("target");
	if (startIndex < 0 \|\| startIndex > target.Length)
	throw new ArgumentOutOfRangeException("startIndex");

	((ICollection<KeyValuePair<string, string>>)_nameValues).CopyTo(target, startIndex);
	}

	#endregion Public Methods

	//------------------------------------------------------
	//
	// Public Operators
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Public Events
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Public Properties
	//
	//------------------------------------------------------

	#region Public Properties

	/// <summary>
	/// The number of name/value pairs in this ContentLocatorPart.
	/// </summary>
	/// <value>count of name/value pairs</value>
	public int Count
	{
	get
	{
	return _nameValues.Count;
	}
	}

	/// <summary>
	/// Indexer provides lookup of values by key. Gets or sets the value
	/// in the ContentLocatorPart for the specified key. If the key does not exist
	/// in the ContentLocatorPart,
	/// </summary>
	/// <param name="key">key</param>
	/// <returns>the value stored in this locator part for key</returns>
	public string this[string key]
	{
	get
	{
	if (key == null)
	{
	throw new ArgumentNullException("key");
	}

	string value = null;
	_nameValues.TryGetValue(key, out value);
	return value;
	}
	set
	{
	if (key == null)
	{
	throw new ArgumentNullException("key");
	}

	if (value == null)
	{
	throw new ArgumentNullException("value");
	}

	string oldValue = null;
	_nameValues.TryGetValue(key, out oldValue);

	// If the new value is actually different, then we add it and fire
	// a change notification
	if ((oldValue == null) \|\| (oldValue != value))
	{
	_nameValues[key] = value;
	FireDictionaryChanged();
	}
	}
	}

	/// <summary>
	///
	/// </summary>
	public bool IsReadOnly
	{
	get
	{
	return false;
	}
	}

	/// <summary>
	/// Returns a collection of all the keys in this ContentLocatorPart.
	/// </summary>
	/// <value>keys</value>
	public ICollection<string> Keys
	{
	get
	{
	return _nameValues.Keys;
	}
	}

	/// <summary>
	/// Returns a collection of all the values in this ContentLocatorPart.
	/// </summary>
	/// <value>values</value>
	public ICollection<string> Values
	{
	get
	{
	return _nameValues.Values;
	}
	}

	#endregion Public Properties

	//------------------------------------------------------
	//
	// Public Events
	//
	//------------------------------------------------------

	//------------------------------------------------------
	//
	// Internal Methods
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Internal Operators
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Internal Events
	//
	//------------------------------------------------------

	#region Public Events

	/// <summary>
	///
	/// </summary>
	public event PropertyChangedEventHandler PropertyChanged;

	#endregion Public Events

	//------------------------------------------------------
	//
	// Internal Properties
	//
	//------------------------------------------------------
	//------------------------------------------------------
	//
	// Private Methods
	//
	//------------------------------------------------------

	#region Private Methods

	/// <summary>
	/// Notify the owner this ContentLocatorPart has changed.
	/// </summary>
	private void FireDictionaryChanged()
	{
	if (PropertyChanged != null)
	{
	PropertyChanged(this, new PropertyChangedEventArgs(null));
	}
	}

	#endregion Private Methods

	//------------------------------------------------------
	//
	// Private Fields
	//
	//------------------------------------------------------

	#region Private Fields

	/// <summary>
	/// The internal data structure.
	/// </summary>
	private Dictionary<string, string> _nameValues;

	#endregion Private Fields
	}
	}

view raw observableStringDictionary.cs hosted with ❤ by GitHub

Our class utilizes two interphases namely Dictionary and INotifyPropertyChanged. The INotifyPropertyChanged and the implemented methods help use to update the data source where the object is binded. As a result when ever the object updated with new values, the control automatically updates.

How to use

Drop the class file to your solution and create an object of our class and also add some values to the dictionary as follows

ObservableDictionary _items = new ObservableDictionary();
_items.UpdateOrAdd("Dev", "Manoj");
_items.UpdateOrAdd("Lan", "C#");
tbl_lan.DataCOntext=_items;
tbl_lan.DataCOntext=_items;

xaml

 <TextBlock x:Name="tbl_dev" TextAlignment="Left" HorizontalAlignment="Left" Text="{Binding [Dev]}" Foreground="LightGoldenrodYellow" />
 <TextBlock x:Name="tbl_lan" TextAlignment="Left" HorizontalAlignment="Left" Text="{Binding [Lan]}" Foreground="LightGoldenrodYellow" />

Go head and customize the class to meet your requirements

Nullable date with Linq and Model class in C#

How to fetch nullable date field from sql server table in C#

In C# Model class you may have experienced a nullable Error while fetching the rows with nullable column from database to your Model objects.

To treat the nullable in proper way , you have to tell your Model class and Linq this is nullable field.

Model class

*The nullable is applied to Value Type .This is not required for string

In the Model class I have a field edate which is in database is a nullable field. I want to make this field nullable in my model

 class StocKBatchModel
    {
        public int B_Id { get; set; }        
        public string Name { get; set; }
        public DateTime? Edate { get; set; }
}

By placing ? after the type of my class property , it becomes nullable. Say the DateTime becomes nullable , I can use the same in Linq in my LInq query as follows

 
var blist = (from m in batch_table.AsEnumerable()                                 
                                 select new
                                 {
                                     obj = new Models.StocKBatchModel()
                                     {
                                         B_Id = m.Field<int>("b_id"),
                                         Name = m.Field<string>("name"),
                                         Edate = m.Field<DateTime?>("exp_date"),                                       
                                 }.obj).ToList();

Hope this will helpful for someone.

Storyboard animation in WPF C#

How to add cool font animation using Event Trigger and Storyboard in WPF C#

WPF allows you to customize the look and feel using XAML and Styles, it allow capable of create some cool animation which is a way of interacting with user and UI. You can use Storyboard with EvenTrigger.

Let’s create a style for a textbox control, which add some color, align text etc ,then add a Style trigger and Event trigger which also add some font animation , want to play while the textbox has focus and lost it’s focus.

The Style

It is a simple style, add font, alignment etc Name the style as NuberTex.

 <Style x:Key="NumberText" TargetType="TextBox">
        <Setter Property="FontSize" Value="18"/>
        <Setter Property="TextAlignment" Value="Right"/>   
        

  </Style>

To use this style add the following lines to the TextBox control (xaml).

 <TextBox  Style="{DynamicResource NumberText}" />

Storyboard

Now we can add a Event trigger and a story board to the above style. First we create a style trigger and then we want to add some style based on Events, namely Gotfocus and Lostfocus.

<Style.Triggers >
            <Trigger Property="IsFocused" Value="True">
                <Setter Property="Foreground" Value="IndianRed"/>
            </Trigger>
            <EventTrigger RoutedEvent="GotFocus">
                <EventTrigger.Actions>
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation Duration="0:0:0:1" To="20" Storyboard.TargetProperty="FontSize" From="18"  />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>
            
            <EventTrigger RoutedEvent="LostFocus">
                <EventTrigger.Actions>
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation Duration="0:0:0:1" From="20" Storyboard.TargetProperty="FontSize" To="18"  />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>
            
        </Style.Triggers>

The storyboard is added within the trigger action. We used a double animation which increase the font from range of values specified using To and From, you can specify what event property you want to play using Target property.

Complete Style

Here is the full style

<Style x:Key="NumberText" TargetType="TextBox">
        <Setter Property="FontSize" Value="18"/>
        <Setter Property="TextAlignment" Value="Right"/>         
        
        <Style.Triggers >
            <Trigger Property="IsFocused" Value="True">
                <Setter Property="Foreground" Value="IndianRed"/>
            </Trigger>
            <EventTrigger RoutedEvent="GotFocus">
                <EventTrigger.Actions>
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation Duration="0:0:0:1" To="20" Storyboard.TargetProperty="FontSize" From="18"  />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>
            
            <EventTrigger RoutedEvent="LostFocus">
                <EventTrigger.Actions>
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation Duration="0:0:0:1" From="20" Storyboard.TargetProperty="FontSize" To="18"  />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>
            
        </Style.Triggers>

    </Style>

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Problem with UI and Worker

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The root : Observable Dictionary

How to use

xaml

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Model class

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The Style

Storyboard

Complete Style

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