/// <summary>
/// Overridden. Starts to create the requested object,
/// either immediately or on a background thread,
/// based on the value of the IsAsynchronous property.
/// </summary>
protected override void BeginQuery()
{
if (this._init)
{
return;
}
if (this._firstRun)
{
this._firstRun = false;
if (!IsInitialLoadEnabled)
{
return;
}
}
if (this._endInitError)
{
// this handles a case where the WPF form initilizer
// invokes the data provider twice when an exception
// occurs - we really don't want to try the query twice
// or report the error twice
this._endInitError = false;
this.OnQueryFinished(null, null, null, null);
return;
}
if (this.IsRefreshDeferred)
{
return;
}
var request = new QueryRequest()
{
DataProducer = this.DataProducer,
Version = this._queryVersion
};
this.IsBusy = true;
AsyncHelper.Invoke(() => DoQuery(request));
}
private void Button1_Click(object sender, EventArgs e)
{
AsyncHelper.Invoke <bool>(PerformOperation);
}
