ptg 524 CHAPTER 11 Using the GridView Control LISTING 11.18 ShowBoundField.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”> <html xmlns=”http://www.w3.org/1999/xhtml” > <head id=”Head1” runat=”server”> <title>Show BoundField</title> </head> <body> <form id=”form1” runat=”server”> <div> <asp:GridView id=”grdMovies” DataSourceID=”srcMovies” AutoGenerateColumns=”false” Runat=”server”> <Columns> <asp:BoundField DataField=”Title” HeaderText=”Movie Title” /> <asp:BoundField DataField=”Director” HeaderText=”Movie Director” /> <asp:BoundField DataField=”BoxOfficeTotals” DataFormatString=”{0:c}” HtmlEncode=”false” HeaderText=”Box Office Totals” /> </Columns> </asp:GridView> <asp:SqlDataSource id=”srcMovies” ConnectionString=”<%$ ConnectionStrings:Movies %>” SelectCommand=”SELECT * FROM Movies” Runat=”server” /> </div> </form> </body> </html> From the Library of Wow! eBook ptg 525 Using Fields with the GridView Control 11 The GridView control includes an AutoGenerateColumns property assigned the value False. If you don’t disable automatically generated columns, both columns represented by the BoundFields and all the columns from the data source display redundantly. In Listing 11.18, BoundFields display the Title, Director, and BoxOfficeTotals columns. The DataField property represents the column that a BoundField displays. The HeaderText property determines the column header. The BoundField used to display the BoxOfficeTotals column includes a DataFormatString property. This format string formats the values of the BoxOfficeTotals column as a currency amount. NOTE For more information about string formatting, see the Formatting Types topic in the Microsoft .NET Framework Documentation. A BoundField supports several other useful properties: . AccessibleHeaderText—Enables you to add an HTML abbr attribute to the column header. . ApplyFormatInEditMode—Enables you to apply the DataFormatString to the field when the row is in edit display mode. . ConvertEmptyStringToNull—Enables you to convert an empty string ”” into the value Nothing (null) when editing a column. . DataField—Enables you to specify the name of the field that the BoundField displays. . DataFormatString—Enables you to use a format string to format a data item. . FooterStyle—Enables you to format the column footer. . FooterText—Enables you to display text in the column footer. . HeaderImageUrl—Enables you to display an image in the column header. . HeaderStyle—Enables you to format the column header. . HeaderText—Enables you to display text in the column header. . HtmlEncode—Enables you to HTML-encode the value of a data item, which enables you to avoid script injection attacks. . InsertVisible—Enables you to not display a column when inserting a new record (does not apply to the GridView control). . ItemStyle—Enables you to format a data item. . NullDisplayText—Enables you to specify text displayed when a data item has the value Nothing (null). From the Library of Wow! eBook ptg 526 CHAPTER 11 Using the GridView Control . ReadOnly—Enables you to prevent the data item from being edited in edit mode. . ShowHeader—Enables you to display the column header. . SortExpression—Enables you to associate a sort expression with the column. . Visible—Enables you to hide a column. Using CheckBoxFields A CheckBoxField, as you can probably guess, displays a check box. When a row is not in edit mode, the check box displays but is disabled. The page in Listing 11.19 illustrates how you can use a CheckBoxField (see Figure 11.14). FIGURE 11.14 Using the CheckBoxField with the GridView control. LISTING 11.19 ShowCheckBoxField.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”> <html xmlns=”http://www.w3.org/1999/xhtml” > <head id=”Head1” runat=”server”> <title>Show CheckBoxField</title> </head> From the Library of Wow! eBook ptg 527 Using Fields with the GridView Control 11 <body> <form id=”form1” runat=”server”> <div> <asp:GridView id=”grdMovies” DataSourceID=”srcMovies” DataKeyNames=”Id” AutoGenerateColumns=”false” AutoGenerateEditButton=”true” Runat=”server”> <Columns> <asp:BoundField DataField=”Title” HeaderText=”Movie Title” /> <asp:CheckBoxField DataField=”InTheaters” HeaderText=”In Theaters” /> </Columns> </asp:GridView> <asp:SqlDataSource id=”srcMovies” ConnectionString=”<%$ ConnectionStrings:Movies %>” SelectCommand=”SELECT Id,Title,InTheaters FROM Movies” UpdateCommand=”UPDATE Movies SET Title=@Title, InTheaters=@InTheaters WHERE Id=@Id” Runat=”server” /> </div> </form> </body> </html> The CheckBoxField inherits from the BoundField class, so it includes all the properties of the BoundField class. It also supports the following property: . Text—Displays text next to each check box. Using CommandFields You can use a CommandField to customize the appearance of the Edit, Delete, Update, Cancel, and Select buttons displayed by the GridView control. For example, the page in Listing 11.20 uses icons for the standard edit buttons (see Figure 11.15). From the Library of Wow! eBook ptg 528 CHAPTER 11 Using the GridView Control LISTING 11.20 ShowCommandField.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”> <html xmlns=”http://www.w3.org/1999/xhtml” > <head id=”Head1” runat=”server”> <title>Show CommandField</title> </head> <body> <form id=”form1” runat=”server”> <div> <asp:GridView id=”grdMovies” DataSourceID=”srcMovies” DataKeyNames=”Id” AutoGenerateColumns=”false” Runat=”server”> <Columns> <asp:CommandField ButtonType=”Image” FIGURE 11.15 Using a CommandField with the GridView control. From the Library of Wow! eBook ptg 529 Using Fields with the GridView Control 11 ShowEditButton=”true” EditText=”Edit Movie” EditImageUrl=”Edit.gif” UpdateText=”Update Movie” UpdateImageUrl=”Update.gif” ShowCancelButton=”true” CancelText=”Cancel Edit” CancelImageUrl=”Cancel.gif” ShowDeleteButton=”true” DeleteText=”Delete Movie” DeleteImageUrl=”Delete.gif” /> <asp:BoundField DataField=”Title” HeaderText=”Movie Title” /> <asp:BoundField DataField=”Director” HeaderText=”Movie Director” /> </Columns> </asp:GridView> <asp:SqlDataSource id=”srcMovies” ConnectionString=”<%$ ConnectionStrings:Movies %>” SelectCommand=”SELECT Id,Title,Director FROM Movies” UpdateCommand=”UPDATE Movies SET Title=@Title, Director=@Director WHERE Id=@Id” DeleteCommand=”DELETE Movies WHERE Id=@Id” Runat=”server” /> </div> </form> </body> </html> You do not enable the AutoGenerateEditButton or AutoGenerateDeleteButton properties when using a CommandField. Instead, you use the CommandField to set up the standard editing buttons explicitly. The CommandField supports the following properties: . ButtonType—Enables you to specify the type of button displayed by the CommandField. Possible values are Button, Image, and Link. . CancelImageUrl—Enables you to specify an image to display for the Cancel button. From the Library of Wow! eBook ptg 530 CHAPTER 11 Using the GridView Control . CancelText—Enables you to specify the text to display for the Cancel button. . CausesValidation—Enables you to disable validation when an Edit button is clicked. . DeleteImageUrl—Enables you to specify an image to display for the Delete button. . DeleteText—Enables you to specify the text to display for the Delete button. . EditImageUrl—Enables you to specify an image to display for the Edit button. . EditText—Enables you to specify the text to display for the Edit button. . InsertImageUrl—Enables you to specify an image to display for the Insert button. . InsertText—Enables you to specify the text to display for the Insert button. . NewImageUrl—Enables you to specify an image to display for the New button (does not apply to GridView). . NewText—Enables you to specify the text to display for the New button. . SelectImageUrl—Enables you to specify the image to display for the Select button. . SelectText—Enables you to specify the text to display for the Select button. . ShowCancelButton—Enables you to display the Cancel button. . ShowDeleteButton—Enables you to display the Delete button. . ShowEditButton—Enables you to display the Edit button. . ShowInsertButton—Enables you to display the Insert button (does not apply to GridView). . ShowSelectButton—Enables you to display the Select button. . UpdateImageUrl—Enables you to specify the image to display for the Update button. . UpdateText—Enables you to specify the text to display for the Update button. . ValidationGroup—Enables you to associate the edit buttons with a validation group. Using Button Fields You use a ButtonField to display a button in a GridView. You can use ButtonField to represent a custom command or one of the standard edit commands. For example, GridView in Listing 11.21 contains two ButtonFields that a user can click to change the display order of the movie category records (see Figure 11.16). From the Library of Wow! eBook ptg 531 Using Fields with the GridView Control 11 LISTING 11.21 ShowButtonField.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”> <script runat=”server”> protected void grdMovieCategories_RowCommand(object sender, ➥GridViewCommandEventArgs e) { int index = Int32.Parse((string)e.CommandArgument); int id = (int)grdMovieCategories.DataKeys[index].Values[“Id”]; int position = (int)grdMovieCategories.DataKeys[index].Values[“Position”]; switch (e.CommandName) { case “Up”: position ; break; case “Down”: position++; break; } srcMovieCategories.UpdateParameters[“Id”].DefaultValue = id.ToString(); FIGURE 11.16 Using ButtonFields with the GridView control. From the Library of Wow! eBook ptg 532 CHAPTER 11 Using the GridView Control srcMovieCategories.UpdateParameters[“Position”].DefaultValue = position.ToString(); srcMovieCategories.Update(); } </script> <html xmlns=”http://www.w3.org/1999/xhtml” > <head id=”Head1” runat=”server”> <title>Show ButtonField</title> </head> <body> <form id=”form1” runat=”server”> <div> <asp:GridView id=”grdMovieCategories” DataSourceID=”srcMovieCategories” DataKeyNames=”Id,Position” AutoGenerateColumns=”false” OnRowCommand=”grdMovieCategories_RowCommand” Runat=”server”> <Columns> <asp:ButtonField Text=”Move Up” CommandName=”Up” /> <asp:ButtonField Text=”Move Down” CommandName=”Down” /> <asp:BoundField DataField=”Position” HeaderText=”Position” /> <asp:BoundField DataField=”Name” HeaderText=”Category Name” /> </Columns> </asp:GridView> <asp:SqlDataSource id=”srcMovieCategories” ConnectionString=”<%$ ConnectionStrings:Movies %>” SelectCommand=”SELECT Id, Name, Position FROM MovieCategories ORDER BY Position” UpdateCommand=”UPDATE MovieCategories SET Position=@Position WHERE Id=@Id” Runat=”server”> <UpdateParameters> From the Library of Wow! eBook ptg 533 Using Fields with the GridView Control 11 <asp:Parameter Name=”Id” /> <asp:Parameter Name=”Position” /> </UpdateParameters> </asp:SqlDataSource> </div> </form> </body> </html> When you click either the Move Up or Move Down buttons in the page in Listing 11.21, the GridView control’s RowCommand event is raised. This event is handled by the grdMovieCategories_RowCommand() method. The grdMovieCategories_RowCommand() method retrieves the index of the row containing the button that was clicked. The row index is grabbed from the GridViewCommandEventArgs’s CommandArgument property passed as the second parameter to the event handler. The grdMovieCategories_RowCommand() method updates the position of a record by setting the SqlDataSource control’s Update parameters and calling the SqlDataSource control’s Update() method. A ButtonField supports the following properties: . ButtonType—Enables you to specify the type of button displayed by the CommandField. Possible values are Button, Image, and Link. . CausesValidation—Enables you to disable validation when the button is clicked. . CommandName—Enables you to associate a standard edit command with the ButtonField. Possible values include Delete, Edit, Update, and Cancel. . DataTextField—Enables you to use a data column to specify the button text. . DataTextFormatString—Enables you to format the button text. . Text—Enables you to specify the button text. . ValidationGroup—Enables you to associate the button with a validation group. You can use CommandName to associate a ButtonField with one of the standard edit commands. For example, you can create a Delete button by assigning the value Delete to the CommandName property. From the Library of Wow! eBook . Library of Wow! eBook ptg 533 Using Fields with the GridView Control 11 < ;asp: Parameter Name=”Id” /> < ;asp: Parameter Name=”Position” /> </UpdateParameters> < /asp: SqlDataSource> </div>. < ;asp: ButtonField Text=”Move Up” CommandName=”Up” /> < ;asp: ButtonField Text=”Move Down” CommandName=”Down” /> < ;asp: BoundField DataField=”Position” HeaderText=”Position” /> < ;asp: BoundField. ptg 5 24 CHAPTER 11 Using the GridView Control LISTING 11.18 ShowBoundField.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC -/ /W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”>