Add Ajax CalendarExtender to a dynamic textBox in ASP.NET C#

Question

Is there a way to add Ajax CalendarExtender to a dynamic ASP.NET textbox control? Basically I'm trying to do the following:

    protected void Page_Load(object sender, EventArgs e)
    {
        database.DB myDB = new database.DB();
        DataTable myVars = new DataTable();

        string myTopicID = (string)Session["myTopicID"];
        bool myInvite = (bool)Session["myInvite"];
        bool mySig = (bool)Session["mySig"];
        string myLogo = (string)Session["myLogo"];
        string myImage = (string)Session["myImage"];
        string myLanguage = (string)Session["myLanguage"];

        myVars = myDB.getVarFields(myTopicID, myLanguage);

        AjaxControlToolkit.CalendarExtender calenderDate = new AjaxControlToolkit.CalendarExtender();

        for (int i = 0; i < myVars.Rows.Count; i++)
        {
            Label label = new Label();
            TextBox text = new TextBox();
            label.Text = Convert.ToString(myVars.Rows[i]["varName"]);
            myPlaceHolder.Controls.Add(label);

            text.ID = Convert.ToString(myVars.Rows[i]["varName"]);

            myPlaceHolder.Controls.Add(new LiteralControl("&nbsp;"));

            myPlaceHolder.Controls.Add(text);

            if (Convert.ToString(myVars.Rows[i]["varName"]).Contains("Date:"))
            {
                calenderDate.TargetControlID = "ContentPlaceHolder1_" + text.ID; 
                myPlaceHolder.Controls.Add(calenderDate);
            }

            myPlaceHolder.Controls.Add(new LiteralControl("<br />"));
        }
    }

The error I get when I run the code above is the following:

The TargetControlID of '' is not valid. A control with ID 'ContentPlaceHolder1_Date:' could not be found. 

Which makes sense I suppose since the actual text box does not exist yet. But is there a way around this?

Answer 1

I think ASP.NET will be smart enough to handle it if you just use text.ID, you shouldn't need to add the ContentPlaceHolder1_ prefix.

If that doesn't work, you can use the TextBox' ClientIdMode property to set it to static, then text.ID will definitely work.

The following code worked locally for me:

AjaxControlToolkit.CalendarExtender calenderDate = new AjaxControlToolkit.CalendarExtender();

            for (int i = 0; i < 2; i++)
            {
                Label label = new Label();
                TextBox text = new TextBox();
                label.Text = Convert.ToString("varName");
                ph1.Controls.Add(label);

                text.ID = "myId" + i;

                ph1.Controls.Add(new LiteralControl("&nbsp;"));

                ph1.Controls.Add(text);


                calenderDate.TargetControlID = text.ID;
                ph1.Controls.Add(calenderDate);


                ph1.Controls.Add(new LiteralControl("<br />"));
            }

Only differences I think you may want to investigate: I'm using latest ControlToolkit from Nuget, I'm using a ToolkitScriptManager instead of default ScriptManager. One thing that may be important to you is making sure you make text.ID unique.