Insert text at the beginning of a text box

问题

I need to insert some text as the first character of my textbox when a button is clicked.

Here is what I have tried:

private void btnInsert_Click(object sender, EventArgs e)
{
    txtMainView.Text.Insert(0, "TEST");
}

This fails to insert the text when I click the button. Anyone have an idea what I am doing wrong?

回答1:

txtMainView.Text = txtMainView.Text.Insert(0, "TEST");

Strings are immutable in .NET Framework so each operation creates a new instance, obviously does not change original string itself!

For more details on String class see MSDN page Strings (C# Programming Guide)

回答2:

Update for c# 6+

txtMainView.Text = $"TEST{txtMainView.Text}";

Original

You can also go with

txtMainView.Text = "TEST" + txtMainView.Text; 

as an alternative.

来源：https://stackoverflow.com/questions/11748451/insert-text-at-the-beginning-of-a-text-box