Display GridView selected record in TextBox by Retaining the previous text using C# in ASP.Net

Hi nedash,

Please use below code.

 C#

protected void LBaddNumber_Click(object sender, EventArgs e)
{
    string numbers = string.Empty;
    GridViewRow row = (sender as Button).NamingContainer as GridViewRow;
    numbers = (row.FindControl("LblNumber") as Label).Text.Trim();
    TxtPhone.Text = numbers.Trim() + Environment.NewLine + TxtPhone.Text;
}