DataSourceInfoCollection.DataSourceRemoved Event

Occurs when removing the data source from the collection.

Namespace: DevExpress.Snap.Core.API

Assembly: DevExpress.Snap.v21.2.Core.dll

NuGet Package: DevExpress.Snap.Core

Declaration

C#

public event EventHandler<DataSourceRemovedEventArgs> DataSourceRemoved

VB.NET

Public Event DataSourceRemoved As EventHandler(Of DataSourceRemovedEventArgs)

Event Data

The DataSourceRemoved event's data class is DataSourceRemovedEventArgs. The following properties provide information specific to this event:

Property	Description
DataSourceInfo	Provides access to information about the target data source.
IsDataSourceInternal	Gets whether the data source is internal (loaded with the document template or added in the UI using the Data Source Wizard) or external (added manually or used in other parts of the application).

Remarks

Handle this event to safely dispose of the data source for further modification.

Before disposing of any data source related to the SnapDocument, check the DataSourceRemovedEventArgs.IsDataSourceInternal property. If true, the retrieved data source was loaded with the report template or added using the Data Source Wizard. This kind of data source can be safely disposed of. Otherwise, the selected data source is external or used in another parts of the application, thus the additional information is required for further operations.

If the data source is removed manually using the DataSourceInfoCollection.Remove method, the event is raised as well.

The code snippet below demonstrates how to safely discard of the data source.

Example

C#

public Form1()
{
  InitializeComponent();
  this.snapControl1.Document.DataSources.DataSourceRemoved += OnDataSourceRemoved;
}     


void OnDataSourceRemoved(object sender, DevExpress.Snap.DataSourceRemovedEventArgs e)
{
  if (e.IsDataSourceInternal)
    {
     IDisposable disposable = e.DataSourceInfo.DataSource as IDisposable;
     if (disposable != null) { disposable.Dispose(); }
    }
 }

VB.NET

Public Sub New()
  InitializeComponent()
  AddHandler Me.snapControl1.Document.DataSources.DataSourceRemoved, AddressOf OnDataSourceRemoved
End Sub


   Private Sub OnDataSourceRemoved(ByVal sender As Object, ByVal e As DevExpress.Snap.DataSourceRemovedEventArgs)
   If e.IsDataSourceInternal Then
    Dim disposable As IDisposable = TryCast(e.DataSourceInfo.DataSource, IDisposable)
      If disposable IsNot Nothing Then  disposable.Dispose()
      End If
     End If
 End Sub