Select Item in DropDown in DataGrid?

Discussion in 'ASP .Net' started by localhost, Dec 22, 2003.

  1. localhost

    localhost Guest

    A DataGrid with shows a label in one of the columns when
    in view mode. When in edit mode, I want to show a
    dropdown, and have the default selection set to what the
    textbox used to be. Right now the first item in the
    dropdown is always displayed.

    Template Code:
    <asp:TemplateColumn HeaderText="DropDown">
    <ItemTemplate>
    <asp:Label runat="server" Text='<%# DataBinder.Eval
    (Container, "DataItem.ChoiceId") %>' ID="lblChoiceId">
    </asp:Label>
    </ItemTemplate>
    <EditItemTemplate>
    <asp:DropDownList ID="ddnChoiceId" runat="server">
    <asp:ListItem Value="Inactive">Inactive</asp:ListItem>
    <asp:ListItem Value="Active">Active</asp:ListItem>
    </asp:DropDownList>
    </EditItemTemplate>
    </asp:TemplateColumn>



    Codebehind:


    protected void OnEdit(object source,
    System.Web.UI.WebControls.DataGridCommandEventArgs eA)
    {
    myGrid.EditItemIndex = eA.Item.DataSetIndex;
    ListItemType ddLister = eA.Item.ItemType;
    if ( ddLister == ListItemType.EditItem )
    {
    DataRowView ddView = eA.Item.DataItem;
    DropDownList ddTemp = eA.Item.FindControl
    ( "ddnChoiceId" );
    // I found the control, now what do I do ?
    //
    }

    Actually, I am not sure if this will work at all.... Any
    suggesstions appreciated. Thanks.
    localhost, Dec 22, 2003
    #1
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  2. localhost

    Jos Guest

    localhost wrote:
    > A DataGrid with shows a label in one of the columns when
    > in view mode. When in edit mode, I want to show a
    > dropdown, and have the default selection set to what the
    > textbox used to be. Right now the first item in the
    > dropdown is always displayed.
    >
    > Template Code:
    > <asp:TemplateColumn HeaderText="DropDown">
    > <ItemTemplate>
    > <asp:Label runat="server" Text='<%# DataBinder.Eval
    > (Container, "DataItem.ChoiceId") %>' ID="lblChoiceId">
    > </asp:Label>
    > </ItemTemplate>
    > <EditItemTemplate>
    > <asp:DropDownList ID="ddnChoiceId" runat="server">
    > <asp:ListItem Value="Inactive">Inactive</asp:ListItem>
    > <asp:ListItem Value="Active">Active</asp:ListItem>
    > </asp:DropDownList>
    > </EditItemTemplate>
    > </asp:TemplateColumn>
    >
    >
    >
    > Codebehind:
    >
    >
    > protected void OnEdit(object source,
    > System.Web.UI.WebControls.DataGridCommandEventArgs eA)
    > {
    > myGrid.EditItemIndex = eA.Item.DataSetIndex;
    > ListItemType ddLister = eA.Item.ItemType;
    > if ( ddLister == ListItemType.EditItem )
    > {
    > DataRowView ddView = eA.Item.DataItem;
    > DropDownList ddTemp = eA.Item.FindControl
    > ( "ddnChoiceId" );
    > // I found the control, now what do I do ?
    > //
    > }
    >
    > Actually, I am not sure if this will work at all.... Any
    > suggesstions appreciated. Thanks.


    I'm assuming from your code that the ChoiceID field contains either
    Active or Inactive.

    Something like this might work:

    foreach (ListItem li in ddTemp.Items)
    if (li.Value == ddView("ChoiceID")) li.Selected=true;

    --

    Jos
    Jos, Dec 22, 2003
    #2
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  3. localhost

    localhost Guest

    Still no go. My codebehind looks like this:

    protected void OnEdit(object source,
    System.Web.UI.WebControls.DataGridCommandEventArgs
    dgCmdEvArgs)
    {
    grdUserAppRoles.EditItemIndex =
    dgCmdEvArgs.Item.DataSetIndex;
    ListItemType ddLister = dgCmdEvArgs.Item.ItemType;
    DataRowView ddView = (DataRowView)
    dgCmdEvArgs.Item.DataItem;
    DropDownList ddTemp = (DropDownList)
    dgCmdEvArgs.Item.FindControl( "ddnChoiceId" );
    foreach (ListItem li in ddTemp.Items)
    {
    if ( li.Value == ddTemp.SelectedValue )
    {
    li.Selected = true;
    }
    }
    .....

    But for starters, ddLister is casting to null.

    Help?



    But
    localhost, Dec 22, 2003
    #3
  4. localhost

    Jos Guest

    localhost wrote:
    > Still no go. My codebehind looks like this:
    >
    > protected void OnEdit(object source,
    > System.Web.UI.WebControls.DataGridCommandEventArgs
    > dgCmdEvArgs)
    > {
    > grdUserAppRoles.EditItemIndex = dgCmdEvArgs.Item.DataSetIndex;


    Stop here with OnEdit, but not before you perform DataBinding:

    grdUserAppRoles.DataBind();
    }

    Then, do the rest in OnItemDataBound:

    protected void OnItemDataBound(object source,
    System.Web.UI.WebControls.DataGridItemEventArgs)

    > ListItemType ddLister = dgCmdEvArgs.Item.ItemType;


    if(ddLister==ListItemType.EditItem) {

    > DataRowView ddView = (DataRowView)
    > dgCmdEvArgs.Item.DataItem;
    > DropDownList ddTemp = (DropDownList)
    > dgCmdEvArgs.Item.FindControl( "ddnChoiceId" );
    > foreach (ListItem li in ddTemp.Items)
    > {
    > if ( li.Value == ddTemp.SelectedValue )
    > {
    > li.Selected = true;
    > }
    > }
    > ....


    Hope this helps...

    --

    Jos
    Jos, Dec 23, 2003
    #4
  5. localhost

    MSFT Guest

    Hi localhost,


    Welcome to Microsoft Newsgroup Service. Based on your problem description,
    you have a DataGrid with a Template column, in which, the ItemTemplate is a
    Lable and the EditItemTemplate is a DropDownList, and you want to set the
    DropDownList's selectedIndex according to the value when show in the
    Label(not in edit mode), is my understanding correct?

    I've tested the code you provided, I found that there are something
    incorrect when run it. Such as :
    DataRowView ddView = eA.Item.DataItem;
    DropDownList ddTemp = eA.Item.FindControl
    ( "ddnChoiceId" );

    the DropDownList hasn't been created at the DataGrid's EditCommand event,
    so we are unable to retrieve it using the "FindControl". Don't worry,
    though we can't retrieve the DropDownList in the DataGrid's EditCommand
    event, there is another way we initialize its value. You can specify a
    "OnLoad" event handler for the DropDownList, for example:
    <asp:TemplateColumn>
    <ItemTemplate>
    <%# DataBinder.Eval(Container.DataItem,"gender") %>
    </ItemTemplate>
    <EditItemTemplate>
    <asp:DropDownList ID="lstGender" OnLoad="lstGender_Load" Runat="server">
    <asp:ListItem Value="male">Male</asp:ListItem>
    <asp:ListItem Value="female">Female</asp:ListItem>
    </asp:DropDownList>
    </EditItemTemplate>
    </asp:TemplateColumn>

    Then, implement this handler function("lstGender_Load") in the Page Class:
    protected void lstGender_Load(object source, System.EventArgs e)
    {
    DropDownList lstGender = (DropDownList)source;
    //get the datasource of the DataGrid(you should change it to other
    //if you don't use DataTAble as the datasource)
    DataTable tb = (DataTable)gridTest.DataSource;
    DataRow row = tb.Rows[gridTest.EditItemIndex];

    if(row["gender"].Equals("male"))
    {
    lstGender.SelectedIndex = 0;
    }
    else
    {
    lstGender.SelectedIndex = 1;
    }

    }


    Then, in the DataGrid's EditCommand event, you just need to set its
    EditItemIndex and rebind the data:

    private void gridTest_EditCommand(object source,
    System.Web.UI.WebControls.DataGridCommandEventArgs e)
    {
    gridTest.EditItemIndex = e.Item.ItemIndex;
    gridTest.DataSource = Get_Data();//Get_Data() returns a DataTable for
    testing
    gridTest.DataBind();
    }

    #notice that the "gridTest_EditCommand" is called before the
    "lstGender_Load", that also indicate that the DropDownList hasn't been
    created when the DataGrid_EditCommand event is fired.

    Please try the preceding suggestion and let me know whether they help.

    Below is my test page and its page class's source

    ----------------DataGridEdit.aspx-----------

    <%@ Page language="c#" Codebehind="DataGridEdit.aspx.cs"
    AutoEventWireup="false" Inherits="MyWebApp.DataGridEdit" %>
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
    <HTML>
    <HEAD>
    <title>DataGridEdit</title>
    <meta content="Microsoft Visual Studio .NET 7.1" name="GENERATOR">
    <meta content="C#" name="CODE_LANGUAGE">
    <meta content="JavaScript" name="vs_defaultClientScript">
    <meta content="http://schemas.microsoft.com/intellisense/ie5"
    name="vs_targetSchema">
    </HEAD>
    <body>
    <form id="Form1" method="post" runat="server">
    <table width="500" align="center">
    <tr>
    <td><asp:datagrid id="gridTest" runat="server"
    AutoGenerateColumns="False">
    <Columns>
    <asp:TemplateColumn>
    <ItemTemplate>
    <%# DataBinder.Eval(Container.DataItem,"id") %>
    </ItemTemplate>
    </asp:TemplateColumn>
    <asp:TemplateColumn>
    <ItemTemplate>
    <%# DataBinder.Eval(Container.DataItem,"name") %>
    </ItemTemplate>
    <EditItemTemplate>
    <input type="text" value='<%#
    DataBinder.Eval(Container.DataItem,"name") %>'/>
    </EditItemTemplate>
    </asp:TemplateColumn>
    <asp:TemplateColumn>
    <ItemTemplate>
    <%# DataBinder.Eval(Container.DataItem,"email") %>
    </ItemTemplate>
    <EditItemTemplate>
    <input type="text" value='<%#
    DataBinder.Eval(Container.DataItem,"email") %>'/>
    </EditItemTemplate>
    </asp:TemplateColumn>
    <asp:TemplateColumn>
    <ItemTemplate>
    <%# DataBinder.Eval(Container.DataItem,"gender") %>
    </ItemTemplate>
    <EditItemTemplate>
    <asp:DropDownList ID="lstGender" OnLoad="lstGender_Load"
    Runat="server">
    <asp:ListItem Value="male">Male</asp:ListItem>
    <asp:ListItem Value="female">Female</asp:ListItem>
    </asp:DropDownList>
    </EditItemTemplate>
    </asp:TemplateColumn>
    <asp:EditCommandColumn ButtonType="LinkButton" UpdateText="Update"
    CancelText="Cancel" EditText="Edit"></asp:EditCommandColumn>
    </Columns>
    </asp:datagrid></td>
    </tr>
    <tr>
    <td><FONT face="ËÎÌå">
    <asp:TextBox id="txtTest" runat="server"></asp:TextBox></FONT>
    </td>
    </tr>
    </table>
    </form>
    </body>
    </HTML>

    ---------------DataGridEdit.aspx.cs-----------------------------
    using System;
    using System.Collections;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Web;
    using System.Web.SessionState;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.Web.UI.HtmlControls;

    namespace MyWebApp
    {
    /// <summary>
    /// Summary description for DataGridEdit.
    /// </summary>
    public class DataGridEdit : System.Web.UI.Page
    {
    protected System.Web.UI.WebControls.TextBox txtTest;
    protected System.Web.UI.WebControls.DataGrid gridTest;

    private void Page_Load(object sender, System.EventArgs e)
    {
    // Put user code to initialize the page here
    if(!IsPostBack)
    {
    gridTest.DataSource = Get_Data();
    gridTest.DataBind();
    }

    }

    protected DataTable Get_Data()
    {
    DataTable tb = new DataTable();
    tb.Columns.Add("id");
    tb.Columns.Add("name");
    tb.Columns.Add("email");
    tb.Columns.Add("gender");

    for(int i=0;i<20;i++)
    {
    DataRow row = tb.NewRow();
    row["id"] = i+1;
    row["name"] = "Name" + i.ToString();
    row["email"] = "Email" + i.ToString();
    if(i%2 == 0)
    {
    row["gender"] = "male";
    }
    else
    {
    row["gender"] = "female";
    }

    tb.Rows.Add(row);
    }

    return tb;

    }

    #region Web Form Designer generated code
    override protected void OnInit(EventArgs e)
    {
    //
    // CODEGEN: This call is required by the ASP.NET Web Form Designer.
    //
    InitializeComponent();
    base.OnInit(e);
    }

    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
    this.gridTest.EditCommand += new
    System.Web.UI.WebControls.DataGridCommandEventHandler(this.gridTest_EditComm
    and);
    this.Load += new System.EventHandler(this.Page_Load);

    }
    #endregion




    protected void lstGender_Load(object source, System.EventArgs e)
    {
    DropDownList lstGender = (DropDownList)source;
    DataTable tb = (DataTable)gridTest.DataSource;
    DataRow row = tb.Rows[gridTest.EditItemIndex];

    if(row["gender"].Equals("male"))
    {
    lstGender.SelectedIndex = 0;
    }
    else
    {
    lstGender.SelectedIndex = 1;
    }

    }

    private void gridTest_EditCommand(object source,
    System.Web.UI.WebControls.DataGridCommandEventArgs e)
    {
    gridTest.EditItemIndex = e.Item.ItemIndex;
    gridTest.DataSource = Get_Data();
    gridTest.DataBind();
    }

    }
    }




    Steven Cheng
    Microsoft Online Support

    Get Secure! www.microsoft.com/security
    (This posting is provided "AS IS", with no warranties, and confers no
    rights.)
    MSFT, Dec 23, 2003
    #5
  6. localhost

    Paul Guest

    Hello Steven,
    I saw your code for the onLoad event for a dropdownlist in a
    datagrid, and that was exactly what I needed for the problem I had
    with a checkboxlist.
    However, I have one problem that I've been trying to figure out.

    I have multiple rows in the grid. How do I pass the index of that row
    to the onload event handler. Here's my code. The checkboxlist have 3
    list items with values B, L and D (Breakfast, Lunch, Dinner).

    Notice the TODO: in the row index.

    Public Sub EditServingType_Load(ByVal source As Object, ByVal e As
    EventArgs)
    Dim servingType As CheckBoxList = CType(source, CheckBoxList)

    Select Case
    CType(CheckDBNull(Me.RestaurantsDataset.Tables(0).Rows(TODO: INDEX
    SHOULD GO HERE)("ServingTypeCode")), String).Trim
    Case "B"
    servingType.Items(0).Selected = True
    Case "L"
    servingType.Items(1).Selected = True
    Case "D"
    servingType.Items(2).Selected = True
    Case "BL"
    servingType.Items(0).Selected = True
    servingType.Items(1).Selected = True
    Case "BD"
    servingType.Items(0).Selected = True
    servingType.Items(2).Selected = True
    Case "LD"
    servingType.Items(1).Selected = True
    servingType.Items(2).Selected = True
    Case "BLD"
    servingType.Items(0).Selected = True
    servingType.Items(1).Selected = True
    servingType.Items(2).Selected = True
    End Select
    End Sub
    Paul, Jan 10, 2004
    #6
  7. localhost

    Guest Guest

    here is the list item

    <EditItemTemplate>




    <asp:CheckBoxList Runat="server"
    Id="EditServingType" OnLoad="EditServingType_Load"
    RepeatDirection="Horizontal">


    <asp:ListItem Value="B">B</asp:ListItem>


    <asp:ListItem Value="L">L</asp:ListItem>


    <asp:ListItem Value="D">D</asp:ListItem>


    </asp:CheckBoxList>


    </EditItemTemplate>


    >-----Original Message-----
    >Hello Steven,
    > I saw your code for the onLoad event for a dropdownlist

    in a
    >datagrid, and that was exactly what I needed for the

    problem I had
    >with a checkboxlist.
    >However, I have one problem that I've been trying to

    figure out.
    >
    >I have multiple rows in the grid. How do I pass the index

    of that row
    >to the onload event handler. Here's my code. The

    checkboxlist have 3
    >list items with values B, L and D (Breakfast, Lunch,

    Dinner).
    >
    >Notice the TODO: in the row index.
    >
    >Public Sub EditServingType_Load(ByVal source As Object,

    ByVal e As
    >EventArgs)
    > Dim servingType As CheckBoxList = CType(source,

    CheckBoxList)
    >
    > Select Case
    >CType(CheckDBNull(Me.RestaurantsDataset.Tables(0).Rows

    (TODO: INDEX
    >SHOULD GO HERE)("ServingTypeCode")), String).Trim
    > Case "B"
    > servingType.Items(0).Selected = True
    > Case "L"
    > servingType.Items(1).Selected = True
    > Case "D"
    > servingType.Items(2).Selected = True
    > Case "BL"
    > servingType.Items(0).Selected = True
    > servingType.Items(1).Selected = True
    > Case "BD"
    > servingType.Items(0).Selected = True
    > servingType.Items(2).Selected = True
    > Case "LD"
    > servingType.Items(1).Selected = True
    > servingType.Items(2).Selected = True
    > Case "BLD"
    > servingType.Items(0).Selected = True
    > servingType.Items(1).Selected = True
    > servingType.Items(2).Selected = True
    > End Select
    > End Sub
    >.
    >
    Guest, Jan 10, 2004
    #7
  8. Hi meritex,


    Thanks for your followup. As for the problem you mentioned---get the
    current editindex of the grid in the list's onload event. I think you can
    add a global variable of the page scope. such as
    class my page: Page
    {
    protected int m_editindex;
    .....


    }

    Then set the value in the Grid's EditCommand event and use it in the
    dropdownlist or checkbox's onload event. Do you think it ok?

    Also, I've found another tech article in MSDN which provides another good
    solution for the databind column in DataGrid.

    http://msdn.microsoft.com/library/en-us/dnaspp/html/creatingcustomcolumns.as
    p?frame=true

    I believe it will be helpful to you.



    Steven Cheng
    Microsoft Online Support

    Get Secure! www.microsoft.com/security
    (This posting is provided "AS IS", with no warranties, and confers no
    rights.)
    Steven Cheng[MSFT], Jan 13, 2004
    #8
    1. Advertising

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