protected void SelectAsync(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback)
{
if (!_owner.DataControl.Page.IsAsync)
{
throw new InvalidOperationException(Resources.ExtendedModelDataSourceView_MustBeAsyncPage);
}
_isAsyncSelect = true;
DataSourceSelectResultProcessingOptions selectResultProcessingOptions = null;
ModelDataSourceMethod modelMethod = EvaluateSelectMethodParameters(arguments, out selectResultProcessingOptions);
ModelDataMethodResult result = InvokeMethod(modelMethod);
_owner.DataControl.Page.RegisterAsyncTask(new PageAsyncTask(async() =>
{
var selectResult = await(Task <SelectResult>) result.ReturnValue;
if (arguments.RetrieveTotalRowCount)
{
if (!selectResult.TotalRowCount.HasValue)
{
throw new InvalidOperationException(Resources.ExtendedModelDataSourceView_TotalRowCountNotSet);
}
arguments.TotalRowCount = selectResult.TotalRowCount.Value;
}
_isAsyncSelect = false;
callback(CreateSelectResult(selectResult.Results));
}));
}
protected override ModelDataSourceMethod EvaluateSelectMethodParameters(DataSourceSelectArguments arguments, out DataSourceSelectResultProcessingOptions selectResultProcessingOptions)
{
if (!_isAsyncSelect)
{
// Not doing async so just delegate to the base
return(base.EvaluateSelectMethodParameters(arguments, out selectResultProcessingOptions));
}
IOrderedDictionary controlValues = MergeSelectParameters(arguments);
ModelDataSourceMethod modelDataSourceMethod = FindMethod(this.SelectMethod);
Type returnType = modelDataSourceMethod.MethodInfo.ReturnType;
Type modelType = ModelType;
if (modelType == null)
{
foreach (var genericTypeArg in returnType.GetGenericArguments())
{
if (typeof(IQueryable <>).MakeGenericType(genericTypeArg).IsAssignableFrom(returnType))
{
modelType = genericTypeArg;
}
}
}
var queryableModelType = (modelType != null) ? typeof(IQueryable <>).MakeGenericType(modelType) : null;
var isReturningQueryable = (queryableModelType != null) && queryableModelType.IsAssignableFrom(returnType);
var autoPage = false;
var autoSort = false;
if ((arguments.StartRowIndex >= 0) && (arguments.MaximumRows > 0))
{
autoPage = IsAutoPagingRequired(modelDataSourceMethod.MethodInfo, isReturningQueryable, _isAsyncSelect);
}
if (!String.IsNullOrEmpty(arguments.SortExpression))
{
autoSort = IsAutoSortingRequired(modelDataSourceMethod.MethodInfo, isReturningQueryable);
}
selectResultProcessingOptions = new DataSourceSelectResultProcessingOptions {
ModelType = modelType, AutoPage = autoPage, AutoSort = autoSort
};
EvaluateMethodParameters(DataSourceOperation.Select, modelDataSourceMethod, controlValues);
return(modelDataSourceMethod);
}
