ASP.NET - 后台获取按钮绑定的值CommandArgument

<asp:LinkButton runat="server" ID="resumelbtn" CommandArgument='<%# Eval("ResumeSource")%>' Text="downloadR" OnClick="downLoadResume"></asp:LinkButton>

public void downLoadResume(object sender, EventArgs e)
    {
        string resumeId = (((LinkButton) sender).CommandArgument.ToString());
    }