Windows Forms FAQ resources

5. Windows Forms Datagrid

5.16 How can I restrict the keystrokes that will be accepted in a column of my datagrid?

You can create a custom column style and handle the KeyPress event of its TextBox member. Below is the code showing how this might be done. You can also download a sample project (C#, VB) that shows an implementation of this idea.

public class DataGridDigitsTextBoxColumn : DataGridTextBoxColumn

{

public DataGridDigitsTextBoxColumn(System.ComponentModel.PropertyDescriptor pd, string format, bool b)

: base(pd, format, b)

{

this.TextBox.KeyPress += new System.Windows.Forms.KeyPressEventHandler(HandleKeyPress);

}

private void HandleKeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)

{

//ignore if not digit or control key

if(!char.IsDigit(e.KeyChar) && !char.IsControl(e.KeyChar))

e.Handled = true;

//ignore if more than 3 digits

if(this.TextBox.Text.Length >= 3 && !char.IsControl(e.KeyChar))

e.Handled = true;

}

protected override void Dispose(bool disposing)

{

if(disposing)

this.TextBox.KeyPress -= new System.Windows.Forms.KeyPressEventHandler(HandleKeyPress);

base.Dispose(disposing);

}