[RESOLVED] Data bind DropDownList inside a repeater contol

[Working.Net]

I am trying to bind a DropDownList inside a repeater control to an existing data set (to be able to edit the data) and I have been searching for an answer to this problem for a day and a half now without any luck. Can anyone point me in the direction of a clear example of how to do this? (Half the time, if you don't know exactly what you are looking for you may find it but never recognize the fact that you have )

Or if you know how to do this and can provide some directions that would probably be cool too.

Thanks

NOTE: Solution is found in post #13

[x-ice]

You haven't posted much information here so I may be misunderstanding your problem.


An example of the ItemDataBound event for a repeater: http://www.codeguru.com/csharp/.net/...cle.php/c12065

You can databind the DropDownList in the ItemDataBound event of the repeater.

[Working.Net]

You haven't posted much information here so I may be misunderstanding your problem.

A valid point x-ice, so I'll give you what I got, and then some more on the bottom. First the ASP for the repeater control:

<asp:Repeater ID="Repeater1" runat="server" >
    <HeaderTemplate>
        <table class="formTbl" border="0" cellspacing="2px">
            <colgroup>
                <col width="75px" />
                <col width="75px" />
                <col width="50px" />
                <col width="60px" />
                <col width="60px" />
                <col width="125px" />
                <col width="100px" />
            </colgroup>
            <tr>
                <td class="top" align="center" colspan="7">Sanitary Pipes Cleaned</td>
            </tr>
            <tr class="grayBack" valign="bottom">
                <td align="center">From MH</td>
                <td align="center">To MH</td>
                <td align="center">Basin</td>
                <td align="right">Footage</td>
                <td align="center">Size</td>
                <td align="center">WorkType</td>
                <td align="center">Times Jetted</td>
            </tr>            		    
            <tr>
                <td colspan="7">
                    <hr />
                </td>
            </tr>
    </HeaderTemplate>
    <ItemTemplate>
            <tr>
                <td align="center">
                    <asp:Label ID="From_MH" runat="server" Text='<%# Eval("UP_MH_NO")%>'></asp:Label>
                </td>
                <td align="center">
                    <asp:Label ID="To_MH" runat="server" Text='<%# Eval("DN_MH_NO")%>'></asp:Label>
                </td>
                <td align="center">
                    <asp:Label ID="Basin" runat="server" Text='<%# Eval("BASIN")%>'></asp:Label>
                </td>
                <td align="right">
                    <asp:Label ID="Asbuilt_Length" runat="server" Text='<%# Eval("ASBUILT_LENGTH")%>'></asp:Label>
                </td>
                <td align="right">
                    <asp:Label ID="Diameter" runat="server" Text='<%# Eval("DIAMETER")%>'></asp:Label>
                </td>
                <td align="center">
                    <asp:DropDownList ID="lstWorkType" runat="server"
                        AutoPostBack="True" width="125px">
                        <asp:ListItem Selected="True">Maintenance</asp:ListItem>
                        <asp:ListItem>Grease</asp:ListItem>
                        <asp:ListItem>Root Cutting</asp:ListItem>
                        <asp:ListItem>Televising</asp:ListItem>
                        <asp:ListItem>Trouble</asp:ListItem>
                    </asp:DropDownList>
                </td>
                <td align="center">
                    <asp:DropDownList ID="lstTimesJetted" runat="server"
                        AutoPostBack="True" width="50px" 
                        OnSelectedIndexChanged="lstTimesJetted_SelectedIndexChanged">
                        <asp:ListItem Selected="True">1</asp:ListItem>
                        <asp:ListItem>2</asp:ListItem>
                        <asp:ListItem>3</asp:ListItem>
                        <asp:ListItem>4</asp:ListItem>
                        <asp:ListItem>5</asp:ListItem>
                        <asp:ListItem>6</asp:ListItem>
                        <asp:ListItem>7</asp:ListItem>
                        <asp:ListItem>8</asp:ListItem>
                        <asp:ListItem>9</asp:ListItem>
                    </asp:DropDownList>
                </td>
            </tr>
            <tr >
                <td align="center">Comment:</td>
                <td colspan="5">
                    <asp:TextBox ID="txtComment" runat="server" Text='<%# Eval("Comment")%>' Width="370px"></asp:TextBox>
                </td>
                <td >
                    <asp:Label ID="PipeID" runat="server" Text='<%# Eval("MAIN_ID")%>'  Visible="false" ></asp:Label>
                </td>
            </tr>
            <tr visible="false" >
                <td >
                    <asp:Label ID="lblWorkType" runat="server" Text='<%# Eval("WorkType")%>'></asp:Label>
                </td>
                <td >
                    <asp:Label ID="lblTimesJetted" runat="server" Text='<%# Eval("TimesJetted")%>'></asp:Label>
                </td>

                <td colspan="5">
                </td>
            </tr>
    </ItemTemplate>
    <SeparatorTemplate>
                <td colspan="7">
                    <hr />
                </td>
    </SeparatorTemplate>
    <FooterTemplate>
        </table>
    </FooterTemplate>
</asp:Repeater>

Code behind:

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim vCleaningId As String

        If Not IsPostBack Then
            vCleaningId = Request.QueryString("CLEANINGID")

            ' Assign the data source GetSanMainRecord to Repeater1 control and DataBind
            ' GetSanCleaningSegmentRecords() returns a datatabel
            Repeater1.DataSource = GetSanCleaningSegmentRecords(vCleaningId)
            Repeater1.DataBind()
        End If
    End Sub

    Sub Repeater1_ItemDataBound(ByVal Sender As Object, _
        ByVal e As RepeaterItemEventArgs) Handles Repeater1.ItemDataBound
        Dim vRepeaterItem As RepeaterItem = e.Item
        Dim vLstWorkType As DropDownList
        Dim vLstTimesJetted As DropDownList
        Dim vLblWorkType As Label
        Dim vLblTimesJetted As Label
        vLstWorkType = DirectCast(vRepeaterItem.FindControl("lstWorkType"), DropDownList)
        vLblWorkType = DirectCast(vRepeaterItem.FindControl("lblWorkType"), Label)
        vLstTimesJetted = DirectCast(vRepeaterItem.FindControl("lstTimesJetted"), DropDownList)
        vLblTimesJetted = DirectCast(vRepeaterItem.FindControl("lblTimesJetted"), Label)

        ' At this point it was my intend to call SetRepeaterDropDownList to
        ' determine and set the recorded value but when I tested for the
        ' listbox it did not yet exist as the exceptions would have me believe.
        ' I think there is supposed to be a way to directly bind the 
        ' DropDdownBox to the data but I could not figure out what 
        ' they were doing in the examples.   

    End Sub

    Protected Sub SetRepeaterDropDownList(ByVal vDropDownList As DropDownList, ByVal vStoredVal As String)
        ' Check each item in lstOperators to see if it matches the stored value
        For i As Integer = 0 To vDropDownList.Items.Count - 1
            'If lstOperators.Items(i).Selected = True Then
            If vDropDownList.Items(i).Text = vStoredVal Then
                ' If the stored value matches the item in the list then set
                ' the selected attribute of the dropdown list item to true.
                vDropDownList.Items(i).Selected = True
            End If
        Next
    End Sub

I looked at the example you provided, and their first instruction:

override protected void OnInit(EventArgs e)
{
   base.OnInit(e);
   rptData.ItemDataBound +=
       new RepeaterItemEventHandler(rptData_ItemDataBound);
}

 Which would translate into:

    Protected Overrides Sub OnInit(ByVal e As EventArgs)
        MyBase.OnInit(e)
        Repeater1.ItemDataBound (*Error 1) += _ 
            New RepeaterItemEventHandler(Repeater1_ItemDataBound (*Error 2))
    End Sub

Gives me the following errors:
Error 1: 'Public Event ItemDataBound(sender As Object, e As
 System.Web.UI.WebControls.RepeaterItemEventArgs)' is an event, and
 cannot be called directly. Use a 'RaiseEvent' statement to raise an event.

Error 2: Delegate 'System.Web.UI.WebControls.RepeaterItemEventHandler'
 requires an 'AddressOf' expression or lambda expression as the only
 argument to its constructor.

[benmartin101]

Try this:

Inside the repeater control

        <FooterTemplate>
            <tr>
                <td>
                    <asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="SqlDataSource1" DataTextField="field1" DataValueField="field1">
                    
                    </asp:DropDownList>
                    <br />
                </td>
            </tr>
        </FooterTemplate>

For the data source, you could either do it on the aspx page itself or programmatically in the code behind. My example will be done on the aspx page.

    <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:SampleDbConnectionString %>"
        SelectCommand="SELECT [field1] FROM [sampletable]"></asp:SqlDataSource>

[benmartin101]

Here's how I would bind a dropdownlist during runtime:

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["SampleDbConnectionString"].ToString());
            string sSQL = "Select name1, age1 from sampletable";
            SqlCommand cmd = new SqlCommand(sSQL, con);
            con.Open();
            SqlDataReader dtrClient = cmd.ExecuteReader();
            DropDownList ddl = (DropDownList)myRepeater.Controls[myRepeater.Controls.Count - 1].FindControl("myDropDownList");
            ddl.DataSource = dtrClient;
            ddl.DataTextField = "name1";
            ddl.DataValueField = "name1";
            ddl.DataBind();

[Working.Net]

benmartin, can you explain what you are doing in post #5, I don't quite understand? As far as I can tell you are returning the second to the last (count -1) control from the controls contained within the repeater. Then from the returned control you are finding (findcontrol) the control named "lstWorkType"

Also, binding the data to the labels and textboxes works OK. Just don't know how to bind the data/display the data in the DropDownBoxes.

Tricky, editing these posts at the same time. I will give what you suggest in 5 a try. Do I do that in the Repeater_ItemDatBound event?

[Working.Net]

OK, I see you are creating and binding the DropDownBox "list" items. That is not the issue here. Sorry if I wasn't clear. I am opening two related tables with a one to many relationship for editing in a form. The repeater displays the "many" part of the relationship. In short I want to display all the records related to the main record, and allow the user to edit them. So the problem is how to display the contents of the fields WorkType and TimesJetted in their corresponding DropDownBoxes.

[benmartin101]

OK, I see you are creating and binding the DropDownBox "list" items. That is not the issue here. Sorry if I wasn't clear. I am opening two related tables with a one to many relationship for editing in a form. The repeater displays the "many" part of the relationship. In short I want to display all the records related to the main record, and allow the user to edit them. So the problem is how to display the contents of the fields WorkType and TimesJetted in their corresponding DropDownBoxes.

I'm a bit confused. So isn't binding basically what you are looking for? Maybe you could give an example of what a user could do with the page, and what you expect would happen.

[Working.Net]

Thanks ben for looking into this. When you are dealing with DropDownBoxes there are two types of data binding that go on. First the kind that populates the list from which the user selects the value that they want stored in the database. The second type of databinding consists of binding the control to the field in the database where the selected value gets stored. When you databind a DropDownBox as you have shown in post #5 the default value is displayed. What I am trying to do is display the data from an existing record. So somehow I have to get the DropDownList to "default" (for lack of a better term) to the value that is coming from the WorkType and TimesJetted fields of the current record.

I did discover that you have to filter for the appropriate ListItemType, in this case ListItemType.Item or ListItemType. AlternatingItem
Like so:

    If (e.Item.ItemType = ListItemType.Item) Or _
        (e.Item.ItemType = ListItemType.AlternatingItem) Then
        ' Do something with the controls here
    End If

[Working.Net]

Take a look at this:

    Sub Repeater1_ItemDataBound(ByVal Sender As Object, ByVal e As RepeaterItemEventArgs) Handles Repeater1.ItemDataBound
        Dim vRepeaterItem As RepeaterItem = e.Item
        Dim vLstTimesJetted As DropDownList
        Dim vLblTimesJetted As Label
        vLstTimesJetted = DirectCast(vRepeaterItem.FindControl("lstTimesJetted"), DropDownList)

        If (e.Item.ItemType = ListItemType.Item) Or _
            (e.Item.ItemType = ListItemType.AlternatingItem) Then
            vLblTimesJetted = DirectCast(vRepeaterItem.FindControl("lblTimesJetted"), Label)
            vLstTimesJetted.ClearSelection()
            For i As Integer = 0 To vLstTimesJetted.Items.Count - 1
                If vLstTimesJetted.Items(i).Text = vLblTimesJetted.Text Then
                    ' If the stored value matches the item in the list then set
                    ' the selected attribute of the dropdown list item to true.
                    vLstTimesJetted.Items(i).Selected = True
                End If
            Next
        End If
    End Sub

Pretty exciting, we're making progress This sort of works. I tested the values, and the comparisons work (If vLstTimesJetted.Items(i).Text = vLblTimesJetted.Text Then) But I get the following error:

An unhandled exception was generated during the execution of the current web request.
Information regarding the origin and location of the exception can be identified
using the exception stack trace below.

Stack Trace:

[HttpException (0x80004005): Cannot have multiple items selected in a DropDownList.]

Which makes me think that I am refering to the same vLstTimesJetted DropDownBox, and not the unique one (as in for each record in the repeater) Any thoughts?

NEVER MIND, HA HA, That is what you get when you don't clear the DropDownBox before setting other items.selected = true. (see blue line in code above) Let me clean this up before I post the final solution. benmartin, thanks for your encouragement and insights

[benmartin101]

But could you give me an example of what happens when a user works with it? Like, like say, user clicks a button, then....what happens with the controls (ie. labels, dropdownlist). What values end up showing?


On your code regarding "Repeater1_ItemDataBound" (I'm assuming this is an event), are you now able to make that whole function work since you can get the dropdownlist control? From my understanding, the SetRepeaterDropDownList() will basically set the selected item based on whether it matches the "vStoredVal". Is that working for you now? If not, why?

edit: this was sent before I could see your last reply

[Working.Net]

Hours of frustration, but then when I finally get to the answers I need to solve the problem and things start falling into place it is all woth it. Ok, maybe not quite like that, but it is cause to celebrate in any event. All in a good day's work.

[Working.Net]

Here is the final solution. The ASP code hasn't changed so you can find that in post #3. I am binding the data in the page_load event (also in post #3) using a function that passes a datatable. The code for the Repeater's ItemDataBound event:

    Sub Repeater1_ItemDataBound(ByVal Sender As Object, ByVal e As RepeaterItemEventArgs) Handles Repeater1.ItemDataBound
        Dim vRepeaterItem As RepeaterItem = e.Item
        Dim vLstWorkType As DropDownList
        Dim vLstTimesJetted As DropDownList
        Dim vLblWorkType As Label
        Dim vLblTimesJetted As Label
        vLstWorkType = DirectCast(vRepeaterItem.FindControl("lstWorkType"), DropDownList)
        vLstTimesJetted = DirectCast(vRepeaterItem.FindControl("lstTimesJetted"), DropDownList)

        If (e.Item.ItemType = ListItemType.Item) Or _
            (e.Item.ItemType = ListItemType.AlternatingItem) Then
            vLblWorkType = DirectCast(vRepeaterItem.FindControl("lblWorkType"), Label)
            vLblTimesJetted = DirectCast(vRepeaterItem.FindControl("lblTimesJetted"), Label)

            SetRepeaterDropDownList(vLstWorkType, vLblWorkType.Text)
            SetRepeaterDropDownList(vLstTimesJetted, vLblTimesJetted.Text)
        End If

    End Sub

    Protected Sub SetRepeaterDropDownList(ByVal vDropDownList As DropDownList, ByVal vStoredVal As String)
        ' Clear current DropDownBox selection
        vDropDownList.ClearSelection()
        ' For each item in the passed DropDownList
        For i As Integer = 0 To vDropDownList.Items.Count - 1
            ' Compare the item's value to the passed value
            If vDropDownList.Items(i).Text = vStoredVal Then
                ' If it matches set the selected attribute of the dropdown list to true.
                vDropDownList.Items(i).Selected = True
            End If
        Next
    End Sub

As a side note and possible continuing discussion, I personally feel that this would be considered a work-around. You should be able to specify that the DropDownBoxes are bound to their respective fields right in the ASP. Thus when you bind the repeater to its data source the DropDownBoxes show their correct values without having to do all this mucking about in the repeater's ItemDataBound event. If I get some good suggestions on this issue I will test them and post the results. For now this thread is done.

[benmartin101]

To be honest, i'm still a bit confused. But as long as you got it working.

[Working.Net]

Which part do you find confusing?

[gep13]

Thus when you bind the repeater to its data source the DropDownBoxes show their correct values without having to do all this mucking about in the repeater's ItemDataBound event. If I get some good suggestions on this issue I will test them and post the results. For now this thread is done.

I would argue that this "mucking" about is actually the correct way to do it.

IMO, adding "eval" and "bind" into your ASPX markup is the wrong approach, as you are mixing the UI portion of the work with the data that you are binding to, and this isn't always the best approach.

Gary

[Working.Net]

Thanks Gary,

It is good to know that you are doing the right thing, especially when it seems like you're just "mucking" about.

[benmartin101]

I kinda got interested in doing this using in a more "binding" way. I figured creating you're own DropDownList would do the trick.

Here's my code for the class:

public class MyDropDownList : DropDownList
    {
        private static int index = 0;
      
	  public MyDropDownList()
        {
    
        }

        //override the OnDataBound event so after data has been bound,
        //you can then set the selected index to the next one using
        //a static integer variable
        protected override void OnDataBound(EventArgs e)
        {
            base.OnDataBound(e);
            this.SelectedIndex = index;
            index++;
        }
    }

Then on your aspx page, you would add this code inside your Repeater:

<cc1:MyDropDownList ID="DropDownList2"  runat="server" DataSourceID="SqlDataSource1" DataTextField="field1" AutoPostBack="true">
            </cc1:MyDropDownList>

Btw, I finally understood what you were trying to do.

edit: maybe this idea was already mentioned in earlier posts, but i think it's a cleaner way of doing it.

[benmartin101]

I kinda got interested in doing this using in a more "binding" way. I figured creating you're own DropDownList would do the trick.

Here's my code for the class:

public class MyDropDownList : DropDownList
    {
        private static int index = 0;
      
	  public MyDropDownList()
        {
    
        }

        //override the OnDataBound event so after data has been bound,
        //you can then set the selected index to the next one using
        //a static integer variable
        protected override void OnDataBound(EventArgs e)
        {
            base.OnDataBound(e);
            this.SelectedIndex = index;
            index++;
        }
    }

Then on your aspx page, you would add this code inside your Repeater:

<cc1:MyDropDownList ID="DropDownList2"  runat="server" DataSourceID="SqlDataSource1" DataTextField="field1" AutoPostBack="true">
            </cc1:MyDropDownList>

Btw, I finally understood what you were trying to do.

edit: maybe this idea was already mentioned in earlier posts, but i think it's a cleaner way of doing it.

edit: Nevermind, currently, this code is no good. The static variable will cause an issue.

[benmartin101]

I figured out a fix. Just add this code in the class:

public class MyDropDownList : DropDownList
    {
        private static int index = 0;
      
	  public MyDropDownList()
        {
    
        }

        //override the OnDataBound event so after data has been bound,
        //you can then set the selected index to the next one using
        //a static integer variable
        protected override void OnDataBound(EventArgs e)
        {
            base.OnDataBound(e);
            this.SelectedIndex = index;
            index++;
        }

//add this
protected override void OnUnload(EventArgs e)
        {
            index=0;
            base.OnUnload(e);
        }
    }