本文整理汇总了VB.NET中System.Data.UniqueConstraint.UniqueConstraint构造函数的典型用法代码示例。如果您正苦于以下问题：VB.NET UniqueConstraint构造函数的具体用法？VB.NET UniqueConstraint怎么用？VB.NET UniqueConstraint使用的例子？那么, 这里精选的构造函数代码示例或许可以为您提供帮助。您也可以进一步了解该构造函数所在类System.Data.UniqueConstraint的用法示例。
在下文中一共展示了UniqueConstraint构造函数的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的VB.NET代码示例。
示例1: CreateUniqueConstraint
Private Sub CreateUniqueConstraint(ByVal dataSetSuppliers As DataSet)
Dim uniqueConstraint As UniqueConstraint
' Get the DataColumn of a table in a DataSet.
Dim dataColumn As DataColumn
dataColumn = dataSetSuppliers.Tables("Suppliers").Columns("SupplierID")
' Create the constraint.
uniqueConstraint = New UniqueConstraint("supplierIdConstraint", dataColumn)
' Add the constraint to the ConstraintCollection of the DataTable.
dataSetSuppliers.Tables("Suppliers").Constraints.Add(uniqueConstraint)
End Sub示例2: MakeTableWithUniqueConstraint
Private Sub MakeTableWithUniqueConstraint()
' Create a DataTable with 2 DataColumns.
Dim dataTable As New DataTable("dataTable")
Dim idColumn As New DataColumn( _
"ID", System.Type.GetType("System.Int32"))
Dim nameColumn As New DataColumn( _
"Name", System.Type.GetType("System.String"))
dataTable.Columns.Add(idColumn)
dataTable.Columns.Add(nameColumn)
' Run procedure to create a constraint.
AddUniqueConstraint(dataTable)
' Add one row to the table.
Dim dataRow As DataRow
dataRow = dataTable.NewRow()
dataRow("ID") = 1
dataRow("Name") = "John"
dataTable.Rows.Add(dataRow)
' Display the constraint name.
Console.WriteLine(dataTable.Constraints(0).ConstraintName)
' Try to add an identical row,
' which throws an exception.
Try
dataRow = dataTable.NewRow()
dataRow("ID") = 1
dataRow("Name") = "John"
dataTable.Rows.Add(dataRow)
Catch ex As Exception
Console.WriteLine("Exception Type: {0}", ex.GetType())
Console.WriteLine("Exception Message: {0}", ex.Message)
End Try
End Sub
Private Sub AddUniqueConstraint(ByVal dataTable As DataTable)
' Create the DataColumn array.
Dim dataColumns(1) As DataColumn
dataColumns(0) = dataTable.Columns("ID")
dataColumns(1) = dataTable.Columns("Name")
' Create the constraint on both columns.
Dim uniqueConstraint As UniqueConstraint = _
New UniqueConstraint("idNameConstraint", dataColumns)
dataTable.Constraints.Add(uniqueConstraint)
End Sub