/// <summary>生成最终的Lambda表达式
///
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public Expression <Func <T, bool> > BuildLambda <T>()
{
DataTable dtFiled = cboFiled.DataSource as DataTable;
if (dtFiled == null)
{
return(null);
}
DataTable dtOperation = cboOperation.DataSource as DataTable;
if (dtOperation == null)
{
return(null);
}
var param = DynamicLinq.CreateLambdaParam <T>("c");
Expression body = Expression.Constant(true); //初始默认一个true
#region 处理优先级
//获取优先级
Dictionary <int, List <TreeGridNode> > dicNodes = GetFirstLevelNodes(tvTaskList);
foreach (KeyValuePair <int, List <TreeGridNode> > item in dicNodes)
{
Expression expressAll = ConvertToFirstLevelFiltersByTreeGridView <T>(param, item.Value);
body = item.Value[0].Cells[0].Value.ToString().Contains("并且") ? body.AndAlso(expressAll) : body.Or(expressAll);
}
#endregion 处理优先级
#region 处理非优先级
//获取非优先级别的Filter
List <TreeGridNode> secNodes = GetSendLevelNodes(tvTaskList);
if (secNodes.Count > 0)
{
List <Filter> filters = ConvertFiltersByTreeGridView(tvTaskList, secNodes);
if (filters.Count > 0)
{
foreach (var filter in filters)
{
Expression express = param.GenerateBody <T>(filter);
if (filter.AndOr == "并且" || filter.AndOr == string.Empty)
{
body = body.AndAlso(express); //这里可以根据需要自由组合
}
else if (filter.AndOr == "或者")
{
body = body.Or(express);
}
}
}
}
#endregion 处理非优先级
var lambda = param.GenerateTypeLambda <T>(body); //最终组成lambda
return(lambda);
}
public static IQueryable <T> Where <T>(this IQueryable <T> query, Filter[] filters)
{
var param = DynamicLinq.CreateLambdaParam <T>("c");
//初始默认一个true
Expression body = Expression.Constant(true);
//foreach (var filter in filters)
//{
// Expression express = param.GenerateBody<T>(filter);
// body = body.AndAlso(express); //这里可以根据需要自由组合
//}
body = filters.Select(filter => param.GenerateBody <T>(filter)).Aggregate(body, (current, express) => current.AndAlso(express));
//最终组成lambda
var lambda = param.GenerateTypeLambda <T>(body);
return(query.Where(lambda));
}
