如何防止在服务器处理完成之前用户多次点击提交按钮(转)

方法一：
代码

protected void Page_Load(object sender, EventArgs e)
{
btn.Attributes.Add("onclick", "state=true;");
StringBuilder sb = new StringBuilder();
sb.Append("if (!state) return;");
sb.Append("var button=document.getElementById('btn');");
sb.Append("button.value='Please Wait...';");
sb.Append("document.body.style.cursor='wait';");
sb.Append("button.disabled=true;");

string strScript = "<script>";
strScript = strScript + "var state=false;";

//将函数绑定到页面的onbeforeunload事件:
strScript = strScript + "window.attachEvent('onbeforeunload',function(){" + sb.ToString() + "});";
strScript = strScript + "</" + "script>";
Page.RegisterStartupScript("onbeforeunload", strScript);

}

protected void Submit_Click(object sender, EventArgs e)
{
//模拟长时间的按钮处理
System.Threading.Thread.Sleep(2000);
Response.Write("<script>alert('bbbbbb!!');" + "</" + "script>");
}

<asp:Button ID="btn" Text="Submit" OnClick="Submit_Click"
runat="server"/>方法2：

<asp:button id="btnSubmit" OnClick="Submit_Click" runat="server" OnClientClick="this.disabled=true;this.form.submit();" UseSubmitBehavior="False"/>

方法3：

this.btnSubmit.Attributes["onclick"]=this.GetPostBackEventReference(this.btnSubmit)+";this.disabled=true;";//防止重复提交