ASP.NET Dynamic Data enables CRUD (Create, Read, Update and Delete) operations in a data model. You can specify the maximum length of characters of each field when inserting and updating data. For character data types, the MaximumLength property identifies the greatest number of bytes required to store a string. If the maximum number of characters is less than 0, the StringLengthAttribute constructor throws an [ArgumentOutOfRangeException].

The following code example limits the number of characters of the ThumbnailPhotoFileName field in the Products Table in AdventureWorksLT database to 4, by applying the StringLength attribute to the Products partial class that represents the Products table.

<MetadataType(GetType(ProductMetadata))> _ 
Public Partial Class Product 


End Class 

Public Class ProductMetadata 


    <ScaffoldColumn(True)> _ 
    <StringLength(10, ErrorMessage := "The file name cannot exceed 10 characters long")> _ 
    Public ProductNumber As Object 


End Class 

[MetadataType(typeof(ProductMetadata))]
public partial class Product
{
    

}

public class ProductMetadata
{

    [ScaffoldColumn(true)]
    [StringLength(10, ErrorMessage= "The file name cannot exceed 10 characters long")]
    public object ProductNumber;


}

To compile the example code, you need the following:

• Visual Studio 2008 Service Pack 1 or Visual Developer 2008 Express Edition Service Pack 1.

• The AdventureWorksLT sample database. For information about how to download and install the SQL Server sample database, see Microsoft SQL Server Product Samples: Database on the CodePlex site. Make sure that you install the correct version of the sample database for the version of SQL Server that you are running (SQL Server 2005 or SQL Server 2008).

• A Dynamic Data Web site. This enables you to create a data context for the database and the class that contains the data field to customize and the methods to override. In addition, it creates the environment in which to use the page described before. For more information, see Walkthrough: Creating a New Dynamic Data Web Site using Scaffolding.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

.NET Framework

Reference