ConstraintCollection.Item[] 属性

定义

命名空间:
System.Data
程序集:
netstandard.dll, System.Data.Common.dll
程序集:
System.Data.Common.dll
程序集:
System.Data.dll
程序集:
netstandard.dll

从集合中获取指定的 Constraint 值。

重载

名称 说明
Item[Int32]

Constraint从集合中获取指定索引处的集合。
Item[String]

Constraint从具有指定名称的集合中获取。

Item[Int32]

Source:
ConstraintCollection.cs
Source:
ConstraintCollection.cs
Source:
ConstraintCollection.cs
Source:
ConstraintCollection.cs
Source:
ConstraintCollection.cs

Constraint从集合中获取指定索引处的集合。

public:
 property System::Data::Constraint ^ default[int] { System::Data::Constraint ^ get(int index); };
public:
 virtual property System::Data::Constraint ^ default[int] { System::Data::Constraint ^ get(int index); };
public System.Data.Constraint this[int index] { get; }
public virtual System.Data.Constraint this[int index] { get; }
member this.Item(int) : System.Data.Constraint
Default Public ReadOnly Property Item(index As Integer) As Constraint
Default Public Overridable ReadOnly Property Item(index As Integer) As Constraint

参数

index
Int32

要返回的约束的索引。

属性值

Constraint

位于 Constraint 指定索引处。

例外

IndexOutOfRangeException

索引值大于集合中的项数。

示例

下面的示例从中Constraint获取每个ConstraintCollection值。

private void GetConstraint(DataTable table)
{
    for(int i = 0; i < table.Constraints.Count; i++)
    {
        Console.WriteLine(table.Constraints[i].ConstraintName);
        Console.WriteLine(table.Constraints[i].GetType());
    }
}

Private Sub GetConstraint(table As DataTable)
    Dim i As Integer
    For i = 0 To table.Constraints.Count - 1
        Console.WriteLine(table.Constraints(i).ConstraintName)
        Console.WriteLine(table.Constraints(i).GetType())
    Next i
 End Sub

注解

Contains使用该方法测试是否存在特定约束。

另请参阅

适用于

Item[String]

Source:
ConstraintCollection.cs
Source:
ConstraintCollection.cs
Source:
ConstraintCollection.cs
Source:
ConstraintCollection.cs
Source:
ConstraintCollection.cs

Constraint从具有指定名称的集合中获取。

public:
 property System::Data::Constraint ^ default[System::String ^] { System::Data::Constraint ^ get(System::String ^ name); };
public:
 virtual property System::Data::Constraint ^ default[System::String ^] { System::Data::Constraint ^ get(System::String ^ name); };
public System.Data.Constraint? this[string? name] { get; }
public System.Data.Constraint this[string name] { get; }
public virtual System.Data.Constraint this[string name] { get; }
member this.Item(string) : System.Data.Constraint
Default Public ReadOnly Property Item(name As String) As Constraint
Default Public Overridable ReadOnly Property Item(name As String) As Constraint

参数

name
String

ConstraintName要返回的约束。

属性值

Constraint

Constraint具有指定名称;否则为 Constraint null 值（如果不存在）。

示例

下面的示例获取命名 Constraint的 。

private void GetConstraint(DataTable table)
{
    if(table.Constraints.Contains("CustomersOrdersConstraint"))
    {
        Constraint constraint =
            table.Constraints["CustomersOrdersConstraint"];
    }
}

Private Sub GetConstraint(table As DataTable)
    If table.Constraints.Contains("CustomersOrdersConstraint") Then
        Dim constraint As Constraint = _
            table.Constraints("CustomersOrdersConstraint")
    End If
End Sub

注解

Contains使用该方法测试是否存在特定约束。

适用于