BindToTypePolicy.QueryBindToType Event

Allows you to spot dynamic loading of a type, check its name and assembly, and allow the type resolve operation.

Namespace: DevExpress.Utils

Assembly: DevExpress.Data.v23.2.dll

NuGet Package: DevExpress.Data

Declaration

C#

public static event BindToTypePolicy.WeakEventHandler<BindToTypePolicy.QueryBindToTypeEventArgs> QueryBindToType

VB.NET

Public Shared Event QueryBindToType As BindToTypePolicy.WeakEventHandler(Of BindToTypePolicy.QueryBindToTypeEventArgs)

Event Data

The QueryBindToType event's data class is BindToTypePolicy.QueryBindToTypeEventArgs. The following properties provide information specific to this event:

Property	Description
Assembly	Gets the assembly that contains the processed type.
AssemblyName	Gets the assembly name. Inherited from BindToTypePolicy.BindToTypeBaseQueryArgs.
AssemblyQualifiedTypeName	Gets the assembly-qualified name of the type, which includes the name of the assembly from which this Type object is being loaded.
Cancel	Gets or sets a value indicating whether the event should be canceled. Inherited from CancelEventArgs.
IsKnownType	Gets whether the type is whitelisted (the type is safe). Inherited from BindToTypePolicy.BindToTypeBaseQueryArgs.
QueryLevel	This member supports the internal infrastructure and is not intended to be used directly from your code. Inherited from BindToTypePolicy.BindToTypeBaseQueryArgs.
Type	Gets or sets the type.
TypeName	Gets the type name.

The event data class exposes the following methods:

Method	Description
ToString()	Returns a string in the following format: “Query Level: {QueryLevel.ToString()}, Requested Type: {AssemblyQualifiedTypeName}”.

Remarks

The BindToTypePolicy fires the QueryBindToType event every time DevExpress UI controls call the Type.GetType() method.

C#

namespace DXApplication {
    internal static class Program {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main() {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            DevExpress.Utils.BindToTypePolicy.QueryBindToType += BindToTypePolicy_QueryBindToType;
            Application.Run(new Form1());
        }
        private static void BindToTypePolicy_QueryBindToType(object sender, DevExpress.Utils.BindToTypePolicy.QueryBindToTypeEventArgs e) {
            if (!e.IsKnownType) {
                // Resolves custom datasource types for DevExpress Reports.
                if (e.TypeName == "ProductsJsonDataSource")
                    e.Type = typeof(ProductsJsonDataSource);
                if (e.TypeName == "UsersJsonDataSource")
                    e.Type = typeof(UsersJsonDataSource);
            }
        }
    }
}

VB.NET

Namespace DXApplication
    Friend Module Program
        ''' <summary>
        ''' The main entry point for the application.
        ''' </summary>
        <STAThread>
        Sub Main()
            Application.EnableVisualStyles()
            Application.SetCompatibleTextRenderingDefault(False)
            AddHandler DevExpress.Utils.BindToTypePolicy.QueryBindToType, AddressOf BindToTypePolicy_QueryBindToType
            Application.Run(New Form1())
        End Sub
        Private Sub BindToTypePolicy_QueryBindToType(ByVal sender As Object, ByVal e As DevExpress.Utils.BindToTypePolicy.QueryBindToTypeEventArgs)
            If Not e.IsKnownType Then
                ' Resolves custom datasource types for DevExpress Reports.
                If e.TypeName = "ProductsJsonDataSource" Then
                    e.Type = GetType(ProductsJsonDataSource)
                End If
                If e.TypeName = "UsersJsonDataSource" Then
                    e.Type = GetType(UsersJsonDataSource)
                End If
            End If
        End Sub
    End Module
End Namespace

Note

Handle the QueryNonTrustedTypeValidation event to validate blacklisted and “unknown” types. The policy does not fire this event to whitelisted/trusted types.

Read the following topic for more information and examples: Safe Deserialization – How to Resolve Unknown Data Types.