Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
Try
Me.BindingContext(objDS, "authors").EndCurrentEdit()
Me.BindingContext(objDS, "authors").SuspendBinding() '临时挂起数据绑定
Me.BindingContext(objDS, "authors").AddNew() '增加新记录
'如下两层循环先找出authors表中不允许为null的列字段,然后找出绑定到该字段的binding对象,
'依据绑定到的控件属性不同来为新增记录中不能为空的字段赋不同初始值
Dim i As Integer
For i = 0 To objDS.authors.Columns.Count - 1 '遍历authors表中所有列字段
'找出authors表中不允许为null的列字段
If objDS.Tables("authors").Columns(i).AllowDBNull = False Then
Dim j As Integer
For j = 0 To Me.BindingContext(objDS, "authors").Bindings.Count - 1 '遍历所有Binding对象
'找出绑定到不允许为null字段的binding对象
If Me.BindingContext(objDS, "authors").Bindings(j).BindingMemberInfo.BindingField = _
objDS.authors.Columns(i).ColumnName Then
'如果绑定到的控件的属性为Text
If BindingContext(objDS, "authors").Bindings(j).PropertyName() = "Text" Then
'新增加记录中不能为null的字段赋初始值"",该语句还可用紧挨着的注释语!