SpatialEdmFunctions.PointCount(DbExpression) 方法
定义
创建 DbFunctionExpression,它使用指定参数(该参数必须具有 Edm.Geography 或 Edm.Geometry 结果类型)调用规范 'PointCount' 函数。Creates a DbFunctionExpression that invokes the canonical 'PointCount' function with the specified argument, which must have an Edm.Geography or Edm.Geometry result type. 该表达式的结果类型为 Edm.Int32。The result type of the expression is Edm.Int32.
public:
[System::Runtime::CompilerServices::Extension]
static System::Data::Common::CommandTrees::DbFunctionExpression ^ PointCount(System::Data::Common::CommandTrees::DbExpression ^ spatialValue);
public static System.Data.Common.CommandTrees.DbFunctionExpression PointCount (this System.Data.Common.CommandTrees.DbExpression spatialValue);
static member PointCount : System.Data.Common.CommandTrees.DbExpression -> System.Data.Common.CommandTrees.DbFunctionExpression
<Extension()>
Public Function PointCount (spatialValue As DbExpression) As DbFunctionExpression
参数
- spatialValue
- DbExpression
一个表达式,在应检索的点数中指定空间行字符串值。An expression that specifies the spatial line string value from which the number of points should be retrieved.
返回
一个新的 DbFunctionExpression,它返回 spatialValue 中的点的数目或返回 null(如果 spatialValue 不是行字符串)。A new DbFunctionExpression that returns either the number of points in spatialValue or null if spatialValue is not a line string.
例外
spatialValue
spatialValue