how do I disable Button asp.net
You can use the client-side onclick event to do that:
yourButton.Attributes.Add("onclick", "this.disabled=true;");
or
You can do this with javascript. in your form tag,
onsubmit="javascript:this.getElementById("submitButton").disabled='true';"
or
In code behind file you can do like this
button1.enabled = false
You have to disable it on client so that user could not click it again.
<asp:button id="btn" runat="server" OnClientClick="this.disabled=true;"......
To disable on server side asp.net code.
btn.Enabled = false;