所属类别：.NET

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用Windows 窗体DataGrid 控件验证输入Windows 窗体 DataGrid 控件有两种可用的输入验证类型。如果用户试图输入一个值，而该值具有单元格不可接受的数据类型（例如，向需要整数的单元格中输入一个字符串），则新的无效值将替换为旧值。这种输入验证是自动完成的，不能进行自定义。另一种的输入验证可用于拒绝任何不可接受的数据，例如，在必须大于或等于 1 的字段中输入 0，或者一个不合适的字符串。这是在数据集中通过编写 DataTable.ColumnChanging 或 DataTable.RowChanging 事件的事件处理程序来完成的。以下示例使用 ColumnChanging 事件，因为“Product”列特别不允许不可接受的值。您可以使用 RowChanging 事件来检查“End Date”列的值是否晚于同一行中“Start Date”的值。验证用户输入 1. 编写代码以处理相应表的 ColumnChanging 事件。当检测到不适当的输入时，调用 DataRow 对象的 SetColumnError 方法。 2. ' Visual Basic3. Private Sub Customers_ColumnChanging(ByVal sender As Object, _4. ByVal e As System.Data.DataColumnChangeEventArgs)5. ' Only check for errors in the Product column6. If (e.Column.ColumnName.Equals("Product")) Then7. ' Do not allow "Automobile" as a product.8. If CType(e.ProposedValue, String) = "Automobile" Then9. Dim badValue As Object = e.ProposedValue10. e.ProposedValue = "Bad Data"11. e.Row.RowError = "The Product column contians an error"12. e.Row.SetColumnError(e.Column, "Product cannot be " & _13. CType(badValue, String))14. End If15. End If16. End Sub17.18. // C#19. //Handle column changing events on the Customers table20. private void Customers_ColumnChanging(object sender, System.Data.DataColumnChangeEventArgs e) {21.22. //Only check for errors in the Product column23. if (e.Column.ColumnName.Equals("Product")) {24.25. //Do not allow "Automobile" as a product26. if (e.ProposedValue.Equals("Automobile")) {27. object badValue = e.ProposedValue;28. e.ProposedValue = "Bad Data";29. e.Row.RowError = "The Product column contains an error";30. e.Row.SetColumnError(e.Column, "Product cannot be " + badValue);31. }32. }}33. 将事件处理程序连接到事件。 将以下代码置于窗体的 Load 事件或其构造函数内。 ' Visual Basic' Assumes the grid is bound to a dataset called customersDataSet1' with a table called Customers.' Put this code in the form's Load event or its constructor.AddHandler customersDataSet1.Tables("Customers").ColumnChanging, AddressOf Customers_ColumnChanging// C#// Assumes the grid is bound to a dataset called customersDataSet1// with a table called Customers.// Put this code in the form's Load event or its constructor.customersDataSet1.Tables["Customers"].ColumnChanging += new DataColumnChangeEventHandler(this.Customers_ColumnChanging); 关闭本页

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