How to manually bind to a control created in ItemCreated event

[JJ]

I have a dropdownlist that was created in a radgrid in the ItemCreated event.  The radgrid is auto-generating the columns, so I have implemented code found elsewhere on the site to replace the textbox control with a dropdownlist.  I have successfully populated the dropdownlist with values at runtime.  Now I wish to bind the new control to the field that the old textbox was bound to.

Here is the code that creates the control in the ItemCreated Event:

                            else if (key == "3")
                            {
                                objtxt.Visible = false;
                                DropDownList drp = new DropDownList();
                                drp.DataSource = dataarray;
                                item[SRfields[valuecount]].Controls.Add(drp);
                                item[SRfields[valuecount]].Controls[1].DataBind(); //don't know if this is required
                            }

How do I bind the new control so the insert and update forms work?

[Shinu]

Hi JJ,

Try replacing the TextBox with DropDownList when the Grid is in edit mode in the ItemDataBound event .

ASPX:

<telerik:GridBoundColumn UniqueName="ProductName"  HeaderText="ProductName" DataField="ProductName" ></telerik:GridBoundColumn>

CS:

 protected void RadGrid1_ItemDataBound(object sender, GridItemEventArgs e)
    {

        if ((e.Item is GridEditableItem) && (e.Item.IsInEditMode))
        {
            GridEditableItem editItem = (GridEditableItem)e.Item;
            DropDownList ddl = new DropDownList();
            ddl.ID = "DropDownList1";
            editItem["ProductName"].Controls.Clear();
            editItem["ProductName"].Controls.Add(ddl);
            //populate the DropDownList
            ddl.DataSource=dataarray
            ddl.DataBind();

        }

    }

note: Also call DataBind() after setting the DataSource for the DropDownList.

Thanks
Shinu.

[JJ]

Shinu,

Thank you for your reply.  I attempted to implement the code but could not do so exactly:

Unfortunately, the field names are not known until runtime; they are dynamically generated.  As a result of this, the ASPX supplied would not be a possibility.  I did otherwise apply the code suggested.  It appears that in my particular context, using the lines:

editItem["fieldname"].Controls.Clear();

editItem["fieldname"].Controls.Add(ddl);

will cause no controls to render for that field if I add it during itemcreated event.  When I add it during the ItemDataBound event, attempting to save a record results in this error:

• Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request.

My previous example did indeed render the control, but did not bind it to the field when adding or update.  I am assuming that this has to do with the fact that the fields are being automatically generated by radgrid during runtime from the supplied datasource.  The various help files alluded to using the itemdatabound event in conjunction with itemcreated for this situation, but I found no code for this manual process.

[JJ]

*bump* Does anyone have a line on this?  The help files talk about it, but there is no example.

[JJ]

Still having this problem; I cannot find a solution.  I would provide more information if I new what to provide.

[JJ]

I did fix this by adding a new dropdownlist control in the itemcreated event.  I then used client-side java to copy the value to the bound field using the client onchange event.  This way the form acts as it would without mucking about in the viewstate.