将查询字符串结果绑定到服务器标签并设置按钮的可见属性

Question

I want to set visible property of button control from design side using server tag <%# %>. I can do it from code behind in page load method by checking query string mode value like below:

if (!IsPostBack)
                {
                    ---

                    if (Request.QueryString["mode"] != null && Request.QueryString["mode"] == "1")
                    {
                        btndelete.Visible = false;
                        ----
                    }
                    else if (Request.QueryString["mode"] != null && Request.QueryString["mode"] == "2")
                    {
                        btndelete.Visible = true;
                        ----    
                    }
                }

Now instead of writing code from code behind i want to check query string mode value from server tag and returned result will be set to Visible property of button.

I have tried this way but No Luck!

<asp:Button ID="btndelete" CausesValidation="false" Text="<%$Resources:General,Delete%>" OnClick="btndelete_Click"
                                runat="server" CssClass="btnstyle" OnClientClick="showConfirm(this,'mdlAttendanceReportCriteriaDelete'); return false;" 
                                Visible='<%#if(Request.QueryString["mode"].ToString() == "1"){Convert.ToBoolean("false")}else{Convert.ToBoolean("true")} %>'/>



 <asp:Button ID="btndelete" CausesValidation="false" Text="<%$Resources:General,Delete%>" OnClick="btndelete_Click"
                                runat="server" CssClass="btnstyle" OnClientClick="showConfirm(this,'mdlAttendanceReportCriteriaDelete'); return false;" 
                                Visible='<%#(Request.QueryString["mode"].ToString() == "1")?Convert.ToBoolean("false"):Convert.ToBoolean("true") %>'/>


<asp:Button ID="btndelete" CausesValidation="false" Text="<%$Resources:General,Delete%>" OnClick="btndelete_Click"
                                runat="server" CssClass="btnstyle" OnClientClick="showConfirm(this,'mdlAttendanceReportCriteriaDelete'); return false;" 
                                Visible='<%#!(Request.QueryString["mode"].ToString() == "1") %>'/>

It run without any parser error but there is no effect at all. Can anybody tell me how to achieve this functionality ?! Thanks in advance.

Answer 1

Call DataBind() method in Page_Load :

protected void Page_Load(object sender, EventArgs e)
{
    DataBind();
}

then use this syntax to set the Visible property in aspx code:

Visible='<%# Request.QueryString["mode"] == "2" %>'

Answer 2

What about using

Visible='<% Request.QueryString.Get("mode") == "1"? "true": "false"%>'

or

Visible='<% if (Request.QueryString.Get("mode") == "1" ) "true" else "false" %>'

Answer 3

Visible='<%# Request.QueryString.Get("mode").Equals("1") ? Convert.ToBoolean("False") : Convert.ToBoolean("True") %>'