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Walkthrough: Retrieving, Updating, Inserting, and Deleting Data with the LinqDataSource and DetailsView Controls

In this walkthrough, you will create a simple database table and a Web page that uses the LinqDataSource control. The Web page enables users to retrieve, update, insert, and delete data from the database table. You will use a DetailsView control to display the data. The LinqDataSource control enables you to perform all these operations without writing Select, Update, Insert, or Delete statements.

You will use the Object Relational Designer to create a class that represents the database table that contains the values. The LinqDataSource control will interact with this generated class to retrieve, update, insert and delete the data.

To implement the procedures in your own development environment you need:

  • Visual Studio 2010 or Visual Web Developer Express.

  • SQL Server Express installed on your computer. If you have SQL Server installed, you can use that instead, but you must make small adjustments to some of the procedures.

  • An ASP.NET Web site.

To perform the steps in this walkthrough, you must have a database table. If you do not already have a table, you can create one by using the following procedure. If you use an existing table, the steps in some of the procedures will not match your database exactly. However, the concepts illustrated in the walkthrough will be the same.

To create a database table

  1. If the Web site does not already have an App_Data folder, in Solution Explorer, right-click the project, click Add ASP.NET Folder, and then click App_Data.

  2. Right click the App_Data folder and then click Add New Item.

  3. Under Installed Templates, select SQL Database, change the file name to Reviews.mdf, and then click Add.

    Add a SQL Database item named Reviews.mdf
  4. In Server Explorer, open the Reviews.mdf node and then right-click the Tables folder.

  5. Click Add New Table.

  6. Create the following columns in the table:

    Column Name

    Data Type

    Properties

    MovieID

    int

    IsIdentity = Yes

    Not null

    Primary Key

    Title

    nvarchar(50)

    Theater

    nvarchar(50)

    Review

    nvarchar(1000)

    Score

    int

    Not null

    Create database table
  7. Save the table and name it MovieReviews.

  8. In Server Explorer, right-click the MovieReviews table and click Show Table Data.

    Open table for adding data.
  9. Manually add values for the fields. You do not have to specify a value for MovieID because that value is generated by the database.

    Add data to the table.

To work with the LinqDataSource control, you work with classes that represent database entities. You can use a tool in Visual Studio 2010 or Visual Web Developer Express to create these classes.

To create a class for the MovieReviews table

  1. If the Web site does not already have an App_Code folder, in Solution Explorer, right-click the project, click Add ASP.NET Folder, and then click App_Code.

  2. Right-click the App_Code folder and then click Add New Item.

  3. Under Installed templates, select Linq to SQL Classes template, rename the file Reviews.dbml, and then click Add.

    Add LINQ to SQL item named Reviews.dbml

    The Object Relational Designer is displayed.

  4. In Server Explorer, drag the MovieReviews table into the Object Relational Designer window.

    The MovieReviews table and its columns are represented as an entity named MovieReview in the designer window.

    Review new table in Object Relational Designer
  5. Save the Reviews.dbml file.

  6. In Solution Explorer, open the Reviews.designer.cs or Reviews.designer.vb file.

    Notice that it now has classes for ReviewsDataContext and MovieReview. The ReviewsDataContext class represents the database and the MovieReview class represents the database table. The parameterless constructor for the ReviewsDataContext class reads the connection string from the Web.config file.

  7. Open the Web.config file.

    Notice that the connection string has been added in the connectionStrings element.

  8. Close the class file and the Web.config file.

Now that you have a database table and classes that represent database entities, you can use a LinqDataSource control on an ASP.NET Web page to manage data.

To create and configure a LinqDataSource control

  1. In Visual Studio, create a new ASP.NET Web page and switch to Design view.

  2. From the Data tab of the Toolbox, drag a LinqDataSource control and drop it inside the form element on the Web page.

    You can leave the ID property as LinqDataSource1.

    Add LinqDataSource control to Design window
  3. In the Smart Tag panel, click Configure Data Source.

    Select Configure Data Source from tasks.
  4. In the Configure Data Source dialog box, select ReviewsDataContext.

    Select the data source.
  5. Set the TableName property to "MovieReviews".

    Select table.

    The following example shows the markup for the LinqDataSource control.

    <asp:LinqDataSource 
      ContextTypeName="ReviewsDataContext" 
      TableName="MovieReviews" 
      ID="LinqDataSource1" 
      runat="server">
    </asp:LinqDataSource>
    

    Notice that you did not have to specify any database commands for selecting the data.

You can now add a DetailsView control and bind it to the LinqDataSource control. The DetailsView control enables users to view data that is managed by the LinqDataSource control.

To connect the data from the LinqDataSource to a DetailsView

  1. Switch to Design view.

  2. From the Data tab of the Toolbox, drag a DetailsView control onto the page.

    You can leave the ID property as DetailsView1.

  3. In the Smart Tag panel, set the data source to LinqDataSource1.

    Set data source.
  4. Select the Enable Paging option.

    The following example shows the markup for the DetailsView control. Notice that the DataKeyNames property was automatically set to the primary key field in the table, and that a bound field was added for each field in the table.

    <asp:DetailsView 
      DataSourceID="LinqDataSource1" 
      DataKeyNames="MovieID" 
      AllowPaging="true" 
      AutoGenerateRows="False"
      ID="DetailsView1" 
      runat="server"
      Height="50px"
      Width="125px">
      <Fields>
        <asp:BoundField 
             DataField="MovieID" 
             HeaderText="MovieID" 
             InsertVisible="False" 
             ReadOnly="True" 
             SortExpression="MovieID" />
        <asp:BoundField 
             DataField="Title" 
             HeaderText="Title" 
             SortExpression="Title" />
        <asp:BoundField 
             DataField="Theater" 
             HeaderText="Theater" 
             SortExpression="Theater" />
        <asp:BoundField 
             DataField="Review" 
             HeaderText="Review" 
             SortExpression="Review" />
        <asp:BoundField 
             DataField="Score" 
             HeaderText="Score" 
             SortExpression="Score" />
      </Fields>
    </asp:DetailsView>
    
  5. Save the changes and then press CTRL+F5 to view the page in a browser.

    The DetailsView control displays the values for the current record from the MovieReviews table.

The LinqDataSource control can create the commands for updating, inserting, and deleting data.

To enable update, insert, and delete operations

  1. In the LinqDataSource control, select the Enable Delete, Enable Insert, and Enable Update options.

    Enable update, insert and delete.

    The following example shows the declarative markup for the LinqDataSource control.

    <asp:LinqDataSource 
      ContextTypeName="ReviewsDataContext" 
      TableName="MovieReviews" 
      EnableUpdate="true" 
      EnableInsert="true" 
      EnableDelete="true" 
      ID="LinqDataSource1" 
      runat="server">
    </asp:LinqDataSource>
    
  2. In the DetailsView control, select the Enable Inserting, Enable Editing, and Enable Deleting options.

    Enable inserting, updating and deleting.

    The following example shows the declarative markup for the DetailsView control.

    <asp:DetailsView 
      DataSourceID="LinqDataSource1" 
      DataKeyNames="MovieID" 
      AutoGenerateRows="false" 
      AllowPaging="true" 
      ID="DetailsView1" 
      runat="server"
      Height="50px" 
      Width="125px">
      <Fields>
        <asp:BoundField 
             DataField="MovieID" 
             HeaderText="MovieID" 
             InsertVisible="False" 
             ReadOnly="True" 
             SortExpression="MovieID" />
        <asp:BoundField 
             DataField="Title" 
             HeaderText="Title" 
             SortExpression="Title" />
        <asp:BoundField 
             DataField="Theater" 
             HeaderText="Theater" 
             SortExpression="Theater" />
        <asp:BoundField 
             DataField="Review" 
             HeaderText="Review" 
             SortExpression="Review" />
        <asp:BoundField 
             DataField="Score" 
             HeaderText="Score" 
             SortExpression="Score" />
        <asp:CommandField 
             ShowDeleteButton="True" 
             ShowEditButton="True" 
             ShowInsertButton="True" />
      </Fields>
    </asp:DetailsView>
    

    The MovieID column is selected from the data source with the other columns. However, it is not displayed in the DetailsView control and the user will not be able to modify its value. The MovieID property must be selected to enable the LinqDataSource control to automatically create the commands for updating, inserting, and deleting data.

    Notice that you did not have to specify commands for these data operations.

  3. Save the changes and press CTRL+F5 to view the page in a browser.

    The DetailsView control displays the fields for the current record from the MovieReviews table. You can update, insert, and delete records by clicking the corresponding buttons on the DetailsView control.

This walkthrough has shown the basic functionality of updating, inserting, and deleting records by using the LinqDataSource control. To learn about additional capabilities of the LinqDataSource control, you can do the following:

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