Textbox with Capital/Uppercase Letter

To convert the text input into the textbox by the user to be converted to capital/uppercase letter:

Design View
<form id="form1" runat="server">
<asp:ScriptManager ID="sc" runat="server"></asp:ScriptManager>
<div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:TextBox ID="TextBox1" runat="server" OnTextChanged="TextBox1_TextChanged" AutoPostBack="true"></asp:TextBox>
</ContentTemplate>
</asp:UpdatePanel>
</div>
</form>

Code Behind
protected void TextBox1_TextChanged(object sender, EventArgs e)
{
TextBox1.Text = TextBox1.Text.ToUpper();

}

Result