Simple example of TextBox control in WPF

When we set the value of the Color in three TextBoxes (Red, Green, Blue) and when we click on the Button the color of the Rectangle will be change. Here we use the Color.FromArgb property of the SolidColorBrush Pattern

For This, First we define the three TextBlocks and TextBoxes for Red, Green and Blue ( txtRedColor, txtRedColor)

<StackPanel Orientation="Horizontal" Margin="9,0,13,0">
      <TextBlock VerticalAlignment="Center" Text="Red Color" Margin="5"></TextBlock>
      <TextBox Name="txtRedColor" Height="25" Width="50"></TextBox>
      <TextBlock VerticalAlignment="Center" Text="Green Color" Margin="5"></TextBlock>
      <TextBox Name="txtGreenColor" Height="25" Width="50"></TextBox>
      <TextBlock VerticalAlignment="Center" Text="Blue Color" Margin="5"></TextBlock>
      <TextBox Name="txtBlueColor" Height="25" Width="50"></TextBox>
</StackPanel>

Now we take a Button Control and a Rectangle:

<Button Name="btnchangeRect" Content="Change Color" Grid.Row="1" Width="100" Height="25"></Button>
<Rectangle Name="rect" Grid.Row="1" Stroke="Azure" StrokeThickness="5" Margin="14,0,26,0" Height="18"
VerticalAlignment="Bottom"></Rectangle>

Here is the Output:



Now we create an EventHandler for the Button control, Here we write the Following Code after the InitializeComponent() in the .cs page

this.btnchangeRect.Click += new RoutedEventHandler(btnchangeRect_Click);

After that we write the code for the Event handler:

void btnchangeRect_Click(object sender, RoutedEventArgs e)
{
    this.rect.Fill = new SolidColorBrush(
    Color.FromArgb(
    255,
    byte.Parse(this.txtRedColor.Text),
    byte.Parse(this.txtGreenColor.Text),
    byte.Parse(this.txtBlueColor.Text)
));

Here Color.FromArgb is used to Set the Color property of SolidColorBrush. Each Color value is in between 0-255. Here R denotes to red, B denotes to Blue, and G denotes to Green.And A is for alpha, which manitains the transparency of the color, So if here we use the value 0 for the complete transparent color.

Here we set the A to 255and set the other three properties( R,G,B) according to the TextBoxes value.