更改文本框的字体样式

Question

I want to change font style for a textbox when I click the button.For this my code is below and it is okay;

 protected void Button1_Click(object sender, System.EventArgs e)  
{  
    TextBox1.Font.Size = FontUnit.XLarge;  
    TextBox1.ForeColor = System.Drawing.Color.Crimson;  
    TextBox1.BackColor = System.Drawing.Color.Snow;  
    TextBox1.BorderColor = System.Drawing.Color.HotPink;  

}  

But Can I do where I select of write which is in the textbox it changes only that part.For example textbox1.Text="Computer Programs" and the user select only "Computer" part of textbox1.Only "Computer" part must be changed.

Answer 1

From the sounds of it you want to format only part of the text? For that you'll need to look at a RichTextBox control.

With a RichTextBox you can make use of text selections and set formatting on only those areas:

RichTextBox rich = new RichTextBox();
rich.Text = "Here is some text for the Rich Text Box";
rich.SelectionStart = 0;
rich.SelectionLength = 4;
rich.SelectionFont = new Font(rich.Font, FontStyle.Bold);

After you're done setting your font to your selection you should set the font immediately afterwards back to the original so that you don't continue the style outside the area you wanted to apply it:

rich.SelectionStart = rich.SelectionStart + rich.SelectionLength;
rich.SelectionLength = 0;
rich.SelectionFont = rich.Font;

This should result in "Here is some text for the Rich Text Box" changing to look like: " Here is some text for the Rich Text Box".