ComplexBinding Control Properties
Unlike simple-bound properties, which must be bound to a single value, complex-bound control properties contain and possibly display multiple items. The most common examples of complex-bound controls are, of course, the ListBox and ComboBox, but any control property that accepts multiple values can be complex-bound. Although the techniques can vary somewhat depending on the specific control, most complex-bound controls are bound by setting the DataSource property directly rather than by adding...
Moving Through Data
Whenever performance and scalability are issues, it's important to limit the amount of data displayed on a single page. For usability reasons, you should always limit the amount of data that is displayed, no matter what the environment users don't appreciate having to wade through masses of data to find the single bit of information they require. One common technique in the Internet environment for limiting the amount of data on a single Web page is to display only a fixed number of rows and...
Chapter 13 Using ADONET in Web Forms
In this chapter, you'll learn how to Display data in a DataGrid control Implement sorting in a DataGrid control Display data in a DataList control Display a DataList control as flowed text Implement paging in a DataGrid control Implement manual navigation in a Web form Use validation controls to control user entry In the previous chapter, we examined the basic data-binding architecture for Web forms. In this chapter, we'll examine a few common data-binding tasks in more detail. Microsoft...
Visual C NET Qad
1. In the form designer, double-click Read Data. Visual Studio adds the event handler to the code. 2. Add the following code to the event handler 3. System.Data.DataSet newDS new System.Data.DataSet XmlReadMode.ReadSchema SetBindings newDS The data.xml file contains an inline schema definition, so by passing the ReadSchema XmlReadMode parameter to the ReadXml method, the code instructs the DataSet to first create the DataSet schema and then load the data. 7. Press F5 to run the application. The...
OnRowUpdated Event
The OnRowUpdated event is raised after the Update method executes the appropriate command against the data source. The event handler for this event is either passed an SqlRowUpdatedEventArgs or an OleDbRowUpdatedEventArgs argument, depending on the Data Provider. Either way, the event argument contains all of the same properties as the RowUpdatingEvent argument, plus an additional property, a read-only RecordsEffected argument that indicates the number of rows that were changed, inserted, or...
DataColumn Expressions
Expressions, technically DataColumn Expressions, are used by the RowFilter and Sort properties of the DataView. We've used DataColumn Expressions in previous chapters when we created a calculated column in a DataTable and when we set the sort and filter expressions for the DataTable Select method. Now it's time to examine them more closely. A DataColumn Expression is a string, and you can use all the normal string handling functions to build one. For example, you can use the amp concatena-tion...
Visual Basic NET Ehw
1. In the code editor, select btnSelect in the ControlName list, and then select Click in the MethodName list. Visual Studio adds the Click event handler template to the code. 2. Add the following code to select only those Customers whose CustomerID begins with A, and rebind the lbCustomers list box to the array of selected rows 3. Dim drFound As System.Data.DataRow 4. Dim dr As System.Data.DataRow 6. drFound LIKE _ amp 'A ' 8. Me.lbClients.DataSource Nothing 15. Press F5 to run the...
Visual C NET Afx
1. Open the Transactions project from the Visual Studio Start Page or by 2. Double-click Transactions.cs to display the form in the form designer. , .-. i i'-pir - -l-'. .v 3 to Tin cfcH'li px-Hl P j Tiwifcufl bfvi T Visual Studio opens the code editor window and adds the Click event handler. 4. Add the following code to the procedure trnNew 9. trnNew 10. strMsg Isolation Level 11. strMsg trnNew.IsolationLevel.ToString The code creates a new Transaction using the default method, and then...
Visual Basic NET Mvk
1. Select btnRollback in the ControlName list, and then select Click in the MethodName list. Visual Studio adds the Click event handler to the code. 2. Add the following lines to the procedure 3. Dim trnNew As System.Data.OleDb.OleDbTransaction 8. trnNew Me.cnAccessNwind.BeginTransactionO trnNew trnNew Committed 16. Catch err As System.Data.OleDb.OleDbException 20. Me.cnAccessNwind.Close End Try This procedure is almost identical to the Commit procedure in the previous exercise. However,...
Visual C NET Yvm
1. In the form designer, double-click Write Data. Visual Studio adds the event handler to the code. 2. Add the following lines to the event handler WriteXml Because no path is passed to the method, the file will be written to the bin subdirectory of the project directory. 7. Press F5 to run the application. The application displays a message box after the file has been written. Rf iHjirMj anil Wntiiiq XML Cataq iylD C ti-igaijiN mc D c c iptiirr Cataq iylD C ti-igaijiN mc D c c iptiirr 9. Close...
Visual Basic NET Qet
1. Select the DataGrid in the form designer, and then click Property Builder in the bottom pane of the Properties window. Visual Studio displays the Property Builder. 2. On the General tab, select the Allow Sorting check box. Visual Studio displays the column headings as link buttons. 4. Press F7 to open the code editor for the page. 5. Select dgCategories in the Control Name combo box, and then select SortCommand in the Method Name combo box. Visual Studio adds the event handler to the code....
Visual Basic NET Qna
1. In the code editor, select btnSort in the ControlName list, and then select Click in the MethodName list. Visual Studio adds the Click event handler template to the code. 2. Add the following code to the method 4. Me.dvOrders.Sort EmployeelD, CustomerlD, OrderlD DESC The code sets the sort order of the dvOrders DataView to sort first by EmployeelD, then by CustomerlD, and finally by OrderlD in descending order. 7. Press F5 to run the application. The application displays the sorted contents...
Visual Basic NET Rsw
1. Add the following lines to the daCategories_RowUpdated event handler that you created in the previous exercise 2. Me.txtMessages.Text amp , amp e.RecordsAffected.ToString amp record s updated. 3. Press F5 to run the application, and then click Fill. 4. Change the CategoryName of Category 1 to Beverages 2, and then The application updates the text in the Messages control. Cx llt 4 HHVd si UKUK UprfWi cwnplttod. I recci Tl updtfed
Visual C NET 1
1. Scroll down to the ConnectionProperties Sub. 2. Add the following lines to the procedure after the InitializeComponent call, filling in the ConnectionString values required for your implementation lt lt add your ConnectionString here gt gt With the Connection objects in place, we can now add the code to display the Connection properties on the sample form. But first, we need to use a little bit of object-oriented sleight of hand in order to accommodate the two different types of objects. One...
Visual Basic NET Emr
1. Press F7 to open the code editor. 2. Add the following procedure, specifying the complete path for the 3. Private Function create_connection As ADODB.Connection 4. Dim dsStr As String Dim dsCn As String Dim cn As New ADODB.Connection dsStr lt lt Specify the path to the Access nwind sample db here gt gt dsCn Source amp _ dsStr amp cn.ConnectionString dsCn
Visual Basic NET Dmk
1. In the code editor, select tbCategoryID in the Control Name combo box, and then select DataBinding in the Method Name combo box. Visual Studio adds the event handler to the code. 2. Add the following line to the procedure Notice that you must explicitly record the first row of the DataTable's DefaultView. This is because Web forms have no CurrencyManager to handle retrieving a current row from the DataSet. 5. Press F5 to run the application. Visual Studio displays the page in the default...
Info Vmc
4. Use the navigation buttons at the bottom of the form to move through the DataSet. Note that all the rows have identical Current and Original versions and that the RowStatus is Unchanged. 5. Change the value of the First Name or Last Name text box of one of the rows, and then click Save. The Current version of the row is updated to reflect the name, and the RowStatus changes to Modified. lt lt lt Empfejce 2 ol 3 gt
Using the BindingContext Object
As we have seen, the BindingContext object is the highest level object in the binding hierarchy and manages the BindingManagerBase objects that control the interaction between a data source and the controls bound to it. The BindingContext object doesn't expose any useful methods or events, and has only a single property, as shown in Table 10-1. The Item property is used to index into the BindingManagerBase collection contained in the BindingContext object. The first version, which uses only the...
Visual C NET Nbq
1. In the form designer, double-click the Clone DataSet button. Visual Studio adds the Click event handler to the code. 2. Add the following code to create the DataRelation strMessage The name of the DataRelation is strMessage 12. Press F5 to run the application. The application adds the DataRelation, and then displays a message box containing the name of the DataRelation. 14. Click OK to close the message box, and then close the application.
Visual Basic NET Eae
1. In the Solution Explorer, right-click Position.aspx, and then select Set Visual Studio displays the page in the form designer. Visual Studio displays the page in the form designer. f- p.tf' C 1 S .--. T.jr i - S1 - - f- - gt - J --------------I - . - . 3. Press F7 to display the code editor. 4. Add the following global declaration to the top of the class 3. Press F7 to display the code editor. 4. Add the following global declaration to the top of the class 5. Public Position as Integer 6....
Command Methods
The methods exposed by the Command object are shown in Table 3-6. Of these, the most important are the four Execute methods ExecuteNonQuery, ExecuteReader, ExecuteScalar, and ExecuteXmlReader. ExecuteNonQuery is used when the SQL command or stored procedure to be executed returns no rows. An Update query, for example, would use the ExecuteNonQuery method. ExecuteScalar is used for SQL commands and stored procedures that return a single value. The most common example of this sort of command is...
Microsoft ADONET Step by Step
Copyright 2002 by Rebecca M. Riordan All rights reserved. No part of the contents of this book may be reproduced or transmitted in any form or by any means without the written permission of the publisher. Library of Congress Cataloging-in-Publication Data Riordan, Rebecca. Microsoft ADO.NET Step by Step Rebecca M. Riordan. p. cm. Includes index. ISBN 0-7356-1236-6 1. Database design. 2. Object oriented programming Computer science 3. ActiveX. I. Title. QA76.9.D26 R56 2002 005.75'85 dc21...