Combo boxes are often used on a form to provide the user with a de ned set of choices in .NET

Encode QR Code 2d barcode in .NET Combo boxes are often used on a form to provide the user with a de ned set of choices
Combo boxes are often used on a form to provide the user with a de ned set of choices
QR Code ISO/IEC18004 Drawer In .NET Framework
Using Barcode generation for .NET framework Control to generate, create QR Code ISO/IEC18004 image in .NET applications.
are:
Recognizing QR Code 2d Barcode In VS .NET
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
The two most common ways to use a combo box in your user interface Programmatic You de ne a list of choices and display them in a combo box When the user makes a selection, you use the selected value in your code to proceed based on the user s choice
Encoding Bar Code In VS .NET
Using Barcode generation for .NET framework Control to generate, create barcode image in .NET framework applications.
Binding to Combo Boxes
Barcode Reader In VS .NET
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
Filtering and item selection are prime examples of programmatic use of a combo box You present a list of choices and the user selects how to filter the data or which item to display The application uses that choice to filter or select the data The Product combo box in the ProductWin form (see Figure 714) illustrates programmatic use of a combo box Data entry You de ne a list of valid values for data entry and display them in a combo box When the user makes a selection, the value is retained When the user selects to save, you store the selection with the form s data The Product Type combo box, shown in Figure 714, provides the user with data entry assistance by offering a list of valid product types The user selects the desired type, and that type is retained with the other product data
Generating QR Code 2d Barcode In Visual C#
Using Barcode encoder for .NET Control to generate, create QR Code JIS X 0510 image in VS .NET applications.
7 BINDING THE USER INTERFACE TO THE BUSINESS OBJECTS
Print QR Code ISO/IEC18004 In VS .NET
Using Barcode generation for ASP.NET Control to generate, create Quick Response Code image in ASP.NET applications.
Why worry about this difference in combo box usage Because the details of binding are slightly different, depending on whether you need the combo box for programmatic use or for end-user data entry
QR Code JIS X 0510 Maker In VB.NET
Using Barcode encoder for .NET framework Control to generate, create Quick Response Code image in VS .NET applications.
Binding a Combo Box for Data Entry
Barcode Printer In .NET Framework
Using Barcode drawer for .NET Control to generate, create barcode image in VS .NET applications.
Combo boxes help users enter valid data into your application by providing a limited list of valid values Examples include a product type, a state or province code, or a payment type (cash, credit card, and so on) Instead of typing in a value, the users select a value from the list Then the users don t need to memorize the list of valid values, and you don t need to write code to ensure that their entered value is valid When you provide a combo box for data entry, you ultimately assign the user s selection to one of the business object class properties For example, the user s selection in a Product Type combo box is assigned to a ProductType property in the Product class To bind to a combo box for data entry: 1 De ne the data structure for the list of valid values in your code Because the binding in Visual Studio allows you to bind to many different types of structures, you have many choices You can use anything from an array to a DataSet to a generic collection, such as a List 2 De ne a property for the data entry value in the business object class
Create Code 39 Extended In VS .NET
Using Barcode maker for Visual Studio .NET Control to generate, create Code 3/9 image in .NET applications.
7
Print Data Matrix In Visual Studio .NET
Using Barcode encoder for .NET framework Control to generate, create Data Matrix 2d barcode image in .NET applications.
Binding the UI to the Business Objects
EAN128 Printer In Visual Studio .NET
Using Barcode generation for .NET framework Control to generate, create EAN / UCC - 14 image in .NET applications.
For the Product Type combo box example, the property is ProductType in the Product class If this property did not previously exist, be sure to build the business object Class Library component after you add this property to ensure that the Data Sources window has access to the new property 3 Set up the binding This step involves setting up the combo box for binding and adding the one line of code that associates the data structure de ned in step 1 with the DataSource property of the BindingSource When binding to a combo box for data entry, three ComboBox control properties need to be set: DisplayMember de nes the property containing the data you want displayed in the combo box This is often a name or description For the Product Type combo box example, this is the logical name of the product type ( Clothing, Leather goods, and so on) ValueMember de nes the property containing the data you want saved when the user makes a selection This is the value that the business object saves with the other business object data If you want to save the actual string product type, you set this to the same property as the DisplayMember For more exibility and changeability, you may want to store a numeric value that is associated with each product type (1, 2, and so on) instead SelectedValue de nes the business object property to which the selected ValueMember is assigned This is the property de ned in step 2 For the Product Type combo box example, this is the ProductType property That s it The binding takes care of the rest When the user drops down the combo box, all the data de ned by the DisplayMember is displayed When the user selects a value from the combo box, the runtime automatically retrieves the information de ned in the ValueMember and assigns it to the property de ned in the SelectedValue These steps are discussed in detail in the next sections
Leitcode Generation In .NET
Using Barcode generation for VS .NET Control to generate, create Leitcode image in VS .NET applications.
Data Matrix 2d Barcode Generation In C#.NET
Using Barcode generator for Visual Studio .NET Control to generate, create Data Matrix image in .NET framework applications.
Encoding GS1 - 13 In Visual Studio .NET
Using Barcode drawer for ASP.NET Control to generate, create GTIN - 13 image in ASP.NET applications.
Bar Code Generator In Java
Using Barcode creation for Java Control to generate, create barcode image in Java applications.
Creating GS1 - 13 In Java
Using Barcode encoder for Java Control to generate, create EAN 13 image in Java applications.