how to add additinol Column(User Demand) dynamically in gridview in asp.net c# when auto generated column property is false

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C#

ASP.NET

SQL

Gridview

I have a Gridview, with existing column ,But i want add some more column with text Box value (column name is textbox value) on button click event (user can add column). Gridview Auto generated Column is false..

<asp:TextBox ID="colmtst" runat="server"></asp:TextBox>
      <asp:Button ID="crtcolm" runat="server" Text="Create Column"
           onclick="crtcolm_Click" />