Question

I have a gridview in an ASP.NET site.

There’s a TemplateField right now that works fine – this is a survey form, and by default questions are answered using textboxes:

<asp:TemplateField HeaderText="" Visible="True" >
   <ItemTemplate>
      <asp:TextBox ID="txtAnswer" Text='<%# Bind("Answer") %>' runat="server" 
       TextMode="MultiLine" Height="76px" MaxLength="2000" Width="377px">
       </asp:TextBox>
    </ItemTemplate>
 <EditItemTemplate>
       <asp:TextBox ID="txtAnswer" Text='<%# Bind("Answer") %>' runat="server" 
       TextMode="MultiLine" Height="76px" MaxLength="2000" Width="377px">
       </asp:TextBox>
 </EditItemTemplate>
 </asp:TemplateField>

The requirement is to now add new questions that may be answered by dropdownlists. I’ve got an idea on how to do this (passing the question number into a function and checking for the presence of dropdown answers that are stored in another table), but I’m struggling with dynamically updating the templatefield based on the question type…any suggestions?

UPDATE

I managed to get this partially working through a helper function. (Probably not my best code, but it’s almost getting the job done) The thing is I get a string that’s telling me the type in my output instead of the actual controls (Textboxes or dropdownlists, respectively)…how can I correct that?

  public Control GetAnswerControl(string QuestionID, string Answer)
{
    List<ListItem> lstOptions = new List<ListItem>();

    SqlCommand cmd = new SqlCommand("pDropDownAnswers_Get", functions.NewSupplierRequest);
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.Add("@QuestionID", SqlDbType.Int);
    cmd.Parameters["@QuestionID"].Value = Int32.Parse(QuestionID);

    try
    {
        functions.NewSupplierRequest.Open();
        SqlDataReader r = cmd.ExecuteReader();
        while (r.Read())
        {
            lstOptions.Add(new ListItem(r["DropDownAnswer"].ToString(), r["DropDownAnswer"].ToString()));
        }
    }
    catch (Exception err)
    {
        this.lblError.Text = err.Message;
    }
    finally
    {
        functions.NewSupplierRequest.Close();
    }

    if (lstOptions.Count == 0)
    {
        TextBox tb = new TextBox();
        tb.ID = "txtAnswer";
        tb.Text = Answer;
        tb.TextMode = TextBoxMode.MultiLine;
        tb.Height = 76;
        tb.Width = 377;
        tb.MaxLength = 2000;

        return tb;
    }
    else
    {
        DropDownList dl = new DropDownList();
        dl.DataSource = lstOptions;
        dl.DataBind();
        dl.SelectedValue = Answer;
        return dl;
    }
}

Answer 1

I wound up getting this to work with a different approach…

1. First I set some hidden fields and a placeholder in the gridview to hold the question ID and answer ID
2. Then I created a helper function to loop through the rows of the gridview, grabbing the ID and answer from the hidden fields.
3. Adding the controls to the placeholder from the codebehind actually formats them as the controls, not the string that I was getting.