How do I get the textbox value to the database within a repeater?

Question

I have a repeater that I populate from a database:

using (SqlConnection conn = new SqlConnection(connString))
{
   SqlCommand cmd = new SqlCommand(@"SELECT CommunityName, CID, Budget FROM Donation WHERE Year = year(getdate()) ORDER BY CommunityName", conn);
   conn.Open();
   SqlDataAdapter adp = new SqlDataAdapter(cmd);
   DataSet myDataSet = new DataSet();
   adp.Fill(myDataSet);
   myRep.ItemDataBound += new RepeaterItemEventHandler(myRep_ItemDataBound);
   myRep.DataSource = myDataSet;
   myRep.DataBind();
}
void myRep_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
   var textbox = e.Item.FindControl("community");
   textbox.ClientIDMode = ClientIDMode.Static;
   textbox.ID = "community" + (e.Item.ItemIndex + 1);
 }

Repeater:

<asp:UpdatePanel ID="UpdatePanel" runat="server" UpdateMode="Always">
    <ContentTemplate>
       <asp:Repeater ID="myRep" runat="server">
          <ItemTemplate>
             <div class="form-group">
                <asp:Label ID='thisLbl' runat="server" Text='<%# Eval("CommunityName") %>' />
                <asp:TextBox runat="server" ID="community" Text='<%# Eval("Budget") %>' CssClass="form-control" />
             </div>
          </ItemTemplate>
       </asp:Repeater>
    </ContentTemplate>
</asp:UpdatePanel>

This creates 6 textboxes with labels and values, now my question is how do I detect which of these boxes belongs to the record it was initially pulled from in the database? I want to be able to modify the value in these boxes and hit a button to save them back to the database but I can't seem to wrap my head around getting them to the proper records.

Should I set the ID of the textbox to something I can parse through and match with the proper record? In the ItemDataBound?

Answer 1

You have to put a hidden field inside the repeater item template that takes the value from budget, and another hidden field to keep the CID value that has to be read in the post back request. Of course you need also a button and its click event handler.

    <asp:Repeater ID="myRep" runat="server">
      <ItemTemplate>
         <div class="form-group">
            <asp:Label ID='thisLbl' runat="server" Text='<%# Eval("CommunityName") %>' />
            <asp:TextBox runat="server" ID="txtBudget" Text='<%# Eval("Budget") %>' CssClass="form-control" />
            <asp:HiddenField runat="server" ID="hdOriginalBudget" Value='<%# Eval("Budget") %>' />
            <asp:HiddenField runat="server" ID="hdCID" Value='<%# Eval("CID") %>' />
         </div>
      </ItemTemplate>
   </asp:Repeater>
    <br />
    <asp:Button ID="btn" runat="server" OnClick="btn_Click" />

In your code behind you need to loop inside the repeater to check whether the text box has been changed by comparing its value to the hidden field. After you save the budget value in the database you need to realign the hidden field value to the the new value entered by the user, otherwise you will always save that value after each post back:

    protected void btn_Click(object sender, EventArgs e)
    {
        foreach (RepeaterItem item  in myRep.Items)
        {
            var txtBudget = item.FindControl("txtBudget") as TextBox;
            var hdOriginalBudget = item.FindControl("hdOriginalBudget") as HiddenField;
            var hdCID = item.FindControl("hdCID") as HiddenField;
            if (txtBudget.Text != hdOriginalBudget.Value)
            { 
                //If you enter here means the user changed the value of the text box

                using (SqlConnection conn = new SqlConnection(connString))
                {
                    SqlCommand cmd = new SqlCommand(@"UPDATE Donation SET Budget = @Budget WHERE CID = @CID", conn);
                    cmd.Parameters.Add(new SqlParameter("@Budget", int.Parse(txtBudget.Text)));
                    cmd.Parameters.Add(new SqlParameter("@CID", int.Parse(hdCID.Value)));
                    conn.Open();
                    cmd.ExecuteNonQuery();
                }

                //After you write in the database realign the values
                hdOriginalBudget.Value = txtBudget.Text; 
            }

        }
    }

Take care that my code is missing the most basic validation, so if the user writes an invalid value in the textbox (for example "yyy") it breaks. So please don't put it in production as it is!