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DataList Control in ASP.NET: Part 5

Posted by Abhimanyu K Vatsa Articles | Visual Basic .NET September 17, 2012
This is my series of articles on the DataList Control and in this article we will discuss how to edit and delete data with a DataList Control.
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Introduction

In Part 4 of this article series we discussed how to select data but now in this article we will discuss how to edit and delete data with a DataList Control.

Edit and Delete Data with DataList Control

We use the DataList control to also edit and delete database records. However, editing with the DataList control requires more coding than editing with other DataBound controls such as the GridView, FormView, or DetailsView controls. The page given below illustrates how to edit and delete database records with the DataList control.

edit-and-delete-operation-in-datalist-in-vb.net.gif

<%@ Page Language="VB" MaintainScrollPositionOnPostback="true" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
   "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<script runat="server">
Protected
Sub dlstMovies_EditCommand(ByVal source As Object, ByVal e As DataListCommandEventArgs)
        dlstMovies.EditItemIndex = e.Item.ItemIndex
        dlstMovies.DataBind()
    End Sub
Protected
Sub dlstMovies_UpdateCommand(ByVal source As Object, ByVal e As DataListCommandEventArgs)
        ' Get form fields
        Dim txtTitle As TextBox = CType(e.Item.FindControl("txtTitle"), TextBox)
        Dim txtDirector As TextBox = CType(e.Item.FindControl("txtDirector"), TextBox)
        Dim chkInTheaters As CheckBox = CType(e.Item.FindControl("chkInTheaters"), CheckBox)
 ' Assign parameters
        srcMovies.UpdateParameters("Id").DefaultValue = dlstMovies.DataKeys(e.Item.ItemIndex).ToString()
        srcMovies.UpdateParameters("Title").DefaultValue = txtTitle.Text
        srcMovies.UpdateParameters("Director").DefaultValue = txtDirector.Text
        srcMovies.UpdateParameters("InTheaters").DefaultValue =chkInTheaters.Checked.ToString()
' Call SqlDataSource Update
        srcMovies.Update()
 ' Take out of Edit mode
        dlstMovies.EditItemIndex = -1
    End Sub
Protected
Sub dlstMovies_DeleteCommand(ByVal source As Object, ByVal e As DataListCommandEventArgs)
        ' Assign parameters
        srcMovies.DeleteParameters("Id").DefaultValue = dlstMovies.DataKeys(e.Item.ItemIndex).ToString()
' Call SqlDataSource Delete
        srcMovies.Delete()
    End Sub
Protected
Sub dlstMovies_CancelCommand(ByVal source As Object, ByVal e As DataListCommandEventArgs)
        dlstMovies.EditItemIndex = -1
        dlstMovies.DataBind()
    End Sub
</script>
<
html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <style type="text/css">
    html
    {
        background-color:silver;
    }
    .content
    {
        background-color:Gray;
    }
    .movies
    {
        background-color:white;
    }
    .movies td,.movies th
    {
        padding:10px;
        border:solid 1px black;
    }
    .edit
    {
        background-color:yellow;
    }
    a
    {
        color:blue;
    }
    </style>
    <title></title>
</head>
<
body>
    <form id="form1" runat="server">
    <div class="content">
 <asp:DataList
        id="dlstMovies"
        DataSourceID="srcMovies"
        DataKeyField="Id"
        GridLines="None"
        OnEditCommand="dlstMovies_EditCommand"
        OnCancelCommand="dlstMovies_CancelCommand"
        OnUpdateCommand="dlstMovies_UpdateCommand"
        OnDeleteCommand="dlstMovies_DeleteCommand"
        CssClass="movies"
        EditItemStyle-CssClass="edit"
        Runat="server">
        <ItemTemplate>
        <b><%#Eval("Title")%></b>
        <br />
        Directed by:
        <%#Eval("Director") %>
        <br />
        In Theaters:
        <%#Eval("InTheaters") %>
        <br /><br />
        <asp:LinkButton
            id="lnkEdit"
            CommandName="Edit"
            Text="Edit"
            Runat="server" />
        &nbsp;|&nbsp;
        <asp:LinkButton
            id="lnkDelete"
            CommandName="Delete"
            Text="Delete"
            OnClientClick="return confirm('Are you sure want to delete?');"
            Runat="server" />
        </ItemTemplate>
        <EditItemTemplate>
        <asp:Label
            id="lblTitle"
            Text="Title:"
            AssociatedControlID="txtTitle"
            Runat="server" />
        <br />
        <asp:TextBox
            id="txtTitle"
            Text='<%#Eval("Title")%>'
            Runat="server" />
        <br /><br />
        <asp:Label
            id="lblDirector"
            Text="Director:"
            AssociatedControlID="txtDirector"
            Runat="server" />
        <br />
        <asp:TextBox
            id="txtDirector"
            Text='<%#Eval("Director")%>'
            Runat="server" />
        <br /><br />
        <asp:CheckBox
            id="chkInTheaters"
            Text="In Theaters"
            Checked='<%#Eval("InTheaters")%>'
            Runat="server" />
        <br /><br />
        <asp:LinkButton
            id="lnkUpdate"
            CommandName="Update"
            Text="Update"
            Runat="server" />
         &nbsp;|&nbsp;
        <asp:LinkButton
            id="lnkCancel"
            CommandName="Cancel"
            Text="Cancel"
            Runat="server" />
        </EditItemTemplate>
    </asp:DataList>
<
asp:SqlDataSource ID="srcMovies" runat="server"
    ConnectionString="<%$ ConnectionStrings:DatabaseConnectionString1 %>"
        ProviderName="<%$ ConnectionStrings:DatabaseConnectionString1.ProviderName %>"
        SelectCommand="SELECT Id,Title,Director,InTheaters
            FROM Movies"
        UpdateCommand="UPDATE Movies SET Title=@Title,
            Director=@Director,InTheaters=@InTheaters
            WHERE Id=@Id"
        DeleteCommand="DELETE Movies WHERE Id=@Id" runat="server">
        <UpdateParameters>
            <asp:Parameter Name="Id" />
            <asp:Parameter Name="Title" />
            <asp:Parameter Name="Director" />
            <asp:Parameter Name="InTheaters" />
        </UpdateParameters>
        <DeleteParameters>
            <asp:Parameter Name="Id" />
        </DeleteParameters>
    </asp:SqlDataSource>
    </div>
    </form>
</body>
</
html>

In above example, the ItemTemplate contained in the DataList includes an Edit LinkButton and a Delete LinkButton. When we click the Edit LinkButton, the DataList raises its EditCommand event and the dlstMovies_Edit() method is executed. Clicking the Delete LinkButton raises the DeleteCommand event and the dlstMovies_Delete() method is executed. The dlstMovies_Edit() method sets the EditItemIndex property of the DataList control. The EditItemTemplate is displayed for the item in the DataList that matches the EditItemIndex. The EditItemTemplate includes form fields for editing a movie record and an Update and Cancel LinkButton. These LinkButtons raise the UpdateCommand and CancelCommand events, and execute the corresponding event handlers.

Note: Continued in the Next Part.

HAVE A GREAT CODING!

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