Displaying and Updating the Data | in Visual Studio .NET

Drawer Quick Response Code in Visual Studio .NET Displaying and Updating the Data |

Click on the Smart Tag of the GridView and check the Enable Selection checkbox. This will cause a Select button to display in the first column of the grid, next to the Edit and Delete buttons already there, as shown in Figure 4-22.

Now all you need to do is set up the event handler to respond to the Select buttons. Double-click on the Select button in the first row of the grid. This will open up the code-behind file with the skeleton of the SelectedIndexChanged already created for you, ready to accept your custom code. Enter the highlighted code from the following snippet:

Protected Sub GridView1_SelectedIndexChanged(ByVal sender As Object, _ ByVal e As System.EventArgs) If GridView1.SelectedRow.RowType = DataControlRowType.DataRow Then Dim cellName As TableCell = GridView1.SelectedRow.Cells(2) ' Name column txtName.Text = cellName.Text End If End Sub

This code first tests to determine if the selected row is a DataRow (as opposed to a HeaderRow or a FooterRow). If it is a DataRow, it creates a variable of type TableCell, which is assigned to the third cell in the selected row (because of zero-based indexing, the third item will have an index value of 2). Then the Text property of the TextBox is set equal to the Text property of that cell.

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Run the app and click on one of the Select buttons. The name from the selected row appears in the TextBox.

Sometimes you do not want to display all the records in a table. For example, you might want to have users select a product from your grid and display the order details for it in a second grid on the current page. To do this, you ll need a way to select a product as well as a way to pass the ID of the selected product to the second grid. The Select buttons are already in place from the previous example, so all you need to do now is pass the ID of the selected product to the second grid. To keep the downloadable source code clear, copy the previous example, AWProductData to a new web site, AWProductDataOrderDetails.

You need to create a second GridView, which will be used to display the order details. From the Toolbox, drag the second GridView onto the page below the first, and then drag the Label and TextBox inside the UpdatePanel. Open the Smart Tag for the UpdatePanel. As you did earlier in the chapter, create a new data source (name it AdventureWorksOrderDetails), but use the existing connection string. Choose the SalesOrderDetail table, select the desired columns (for this example, SalesOrderID, CarrierTrackingNumber, OrderQty, UnitPrice, UnitPriceDiscount, and LineTotal), and then click the Where button, as shown in Figure 4-23. A WHERE clause is a SQL language keyword used to narrow the set of data returned by the SELECT statement. In other words, you re saying, Get me all the records from this table, where this condition is true. The condition could be defined any number of ways where the amount in inventory is less than 10, where the customer name is Smith, or where the copyright date is after 1985. It all depends on the types of information you have stored in your columns. When you click the WHERE button, the Add WHERE Clause dialog opens, which you can see in Figure 4-24. First, you pick the column you want to match on, in this case ProductID. Next, pick the appropriate operator for your condition statement. Your choices include among others, equal to, less than/greater than, like, and contains. For this exercise, use the default (=). The third drop-down lets you pick the source for the ProductID that is, where you will get the term you want to match on. You can pick from any one of several objects in the menu or choose None if you ll be providing a source manually. In this case, you ll obtain the source of the ProductID from the first GridView, so choose Control.