DbExpressionBuilder.Project(DbExpressionBinding, DbExpression) 方法
定义
创建一个新的 DbProjectExpression,它对给定的输入集投影指定的表达式。Creates a new DbProjectExpression that projects the specified expression over the given input set.
public:
[System::Runtime::CompilerServices::Extension]
static System::Data::Common::CommandTrees::DbProjectExpression ^ Project(System::Data::Common::CommandTrees::DbExpressionBinding ^ input, System::Data::Common::CommandTrees::DbExpression ^ projection);
public static System.Data.Common.CommandTrees.DbProjectExpression Project (this System.Data.Common.CommandTrees.DbExpressionBinding input, System.Data.Common.CommandTrees.DbExpression projection);
static member Project : System.Data.Common.CommandTrees.DbExpressionBinding * System.Data.Common.CommandTrees.DbExpression -> System.Data.Common.CommandTrees.DbProjectExpression
<Extension()>
Public Function Project (input As DbExpressionBinding, projection As DbExpression) As DbProjectExpression
参数
- input
- DbExpressionBinding
一个指定输入集的表达式绑定。An expression binding that specifies the input set.
- projection
- DbExpression
要对集投影的表达式。An expression to project over the set.
返回
表示投影运算的新 DbProjectExpression。A new DbProjectExpression that represents the projection operation.
例外
input 或 projection 为 null。input or projection is null.