JsonDataSource.FillError Event

Occurs when an attempt to fill the data source fails.

Namespace: DevExpress.DataAccess.Json

Assembly: DevExpress.DataAccess.v20.2.dll

NuGet Packages: DevExpress.DataAccess, DevExpress.WindowsDesktop.DataAccess

Declaration

C#

public event DataSourceFillErrorEventHandler FillError

VB.NET

Public Event FillError As DataSourceFillErrorEventHandler

Event Data

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

Property	Description
ConnectionName	Specifies the name of the JSON data source connection that was used when the FillError event occurred.
Exception	Gets the exception that caused the FillError event.
Handled	Gets or sets whether the FillError event has been handled.

Remarks

This event occurs when a call to the Fill() method fails to populate the data source with data. Handle this event to process the following exceptions:

• WebExceptions that occur when the endpoint’s Uri is not accessible.
• IOExceptions that occur on failed attempts to load JSON data from the file system.
• JSON data parse errors.

Use the following properties to retrieve the exception details:

• DataSourceFillErrorEventArgs.ConnectionName - the name of the connection that was used when the FillError event occurred.
• DataSourceFillErrorEventArgs.Exception - the data source exception that was thrown. This is a WebException, IOException, or a parse exception.
• DataSourceFillErrorEventArgs.Handled - specifies if the exception is handled.

The JsonDataSourceException exception occurs instead of the WebException, IOException, and parse errors. Catch this exception as an alternative to the FillError event.

C#

try {
  dataSource.Fill()
}
catch(JsonDataSourceException e) {
  //do something
}

VB.NET

Try
  dataSource.Fill()
Catch e As JsonDataSourceException
  'do something
End Try

Example

The code sample below creates a new data source, handles the FillError event to to process exceptions, and tries to populate the data source with data.

C#

using DevExpress.DataAccess.Json;
// ...
// Create a new JSON source.
var jsonSource = new UriJsonSource() {
    Uri = new Uri(@"https://invalid.json")
};
// Assign the JSON source to the data source.
var datasource = new JsonDataSource() {
    JsonSource = jsonSource
};
dataSource.FillError += (s, e) => {
    e.Handled = true;
    // Add code that handles the data source fill error here.
};

VB.NET

Imports DevExpress.DataAccess.Json
' ...
' Create a new JSON source.
Private jsonSource = New UriJsonSource() With {.Uri = New Uri("https://invalid.json")}
' Assign the JSON source to the data source.
Private datasource = New JsonDataSource() With {.JsonSource = jsonSource}
Private dataSource.FillError += Sub(s, e) e.Handled = True