/// <summary> /// 从基础数据存储获取数据列表。 /// </summary> /// <param name="arguments"></param> /// <returns></returns> protected internal abstract IEnumerable ExecuteSelect(DataSourceSelectArgumentsEx arguments);
/// <summary>
/// 从基础数据存储中异步获取数据列表。
/// </summary>
/// <param name="arguments">用于请求对数据执行基本数据检索以外的操作。</param>
/// <param name="callback">用于在异步操作完成时通知数据绑定控件的 <see cref="DataSourceViewSelectCallback"/> 委托。</param>
public virtual void Select(DataSourceSelectArgumentsEx arguments, DataSourceViewSelectCallback callback)
{
if (callback == null)
throw new ArgumentNullException("callback");
callback(this.ExecuteSelect(arguments));
}
/// <summary>
/// 创建 <see cref="DataSourceSelectArgumentsEx"/> 对象，该对象包含传递到数据源进行处理的参数。
/// </summary>
/// <returns></returns>
protected override DataSourceSelectArgumentsEx CreateDataSourceSelectArguments()
{
DataSourceSelectArgumentsEx arguments = new DataSourceSelectArgumentsEx();
DataSourceViewEx data = this.GetData();
string sortExpressionInternal = this.SortExpression;
if ((this.SortDirection == SortDirection.Descending) && !string.IsNullOrEmpty(sortExpressionInternal))
sortExpressionInternal += " DESC ";
arguments.SortExpression = sortExpressionInternal;
if (this.AllowPaging && data.CanPage)
{
if (data.CanRetrieveTotalRowCount)
{
arguments.RetrieveTotalRowCount = true;
arguments.MaximumRows = this.PageSize;
}
else
arguments.MaximumRows = -1;
arguments.StartRowIndex = this.PageSize * this.PageIndex;
}
return arguments;
}
/// <summary>
///
/// </summary>
/// <param name="arguments"></param>
/// <returns></returns>
protected internal override IEnumerable ExecuteSelect(DataSourceSelectArgumentsEx arguments)
{
//arguments.RaiseUnsupportedCapabilitiesError(this);
return this.dataSource;
}
/// <summary>
/// 从关联的数据源中检索数据。
/// </summary>
protected override void PerFormSelect()
{
this.OnDataBinding(EventArgs.Empty);
DataSourceViewEx data = this.GetData();
this.arguments = this.CreateDataSourceSelectArguments();
this.ignoreDataSourceViewChanged = true;
base.RequiresDataBinding = false;
this.MarkAsDataBound();
data.Select(this.arguments, new DataSourceViewSelectCallback(this.OnDataSourceViewSelectCallback));
}