Question

在我的Windows应用程序中，有一个DataGridView表单，显示来自xml文件的数据。

现在，我想检查DataGridView是否有任何更改，以询问用户是否“她想要将DataGridView中已完成的当前更改保存到文件中。

Answer 1

我会使用两个事件来检测DataGridView中的任何变化。这些CellValueChanged用于检测字段的更改，CurrentCellDirtyStateChanged用于检测CheckBox类型列中的更改。

当其中任何一个事件发生时设置一个布尔值flag = true，并在表单关闭时或者当您要求用户保存更改时检查此标志的状态。

示例代码

Dim DGVhasChanged As Boolean

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    DGVhasChanged = False

    //Do stuff to populate the DataGridView

End Sub

Private Sub DataGridView1_CellValueChanged(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellValueChanged

    DGVhasChanged = True

End Sub    

Private Sub DataGridView1_CurrentCellDirtyStateChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DataGridView1.CurrentCellDirtyStateChanged

    DGVhasChanged = True

End Sub    

//This example check for changes on Form closing but you can check it on any other event (e.g: When a button is clicked)
Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing

   If DGVhasChanged = True Then           
       Dim response As MsgBoxResult  
       response = MsgBox("Do you want to save the changes?", MsgBoxStyle.YesNo)
       If response = MsgBoxResult.Yes Then
           //Do stuff to save the changes...
           DGVhasChanged= False
       End If
   End If

End Sub

Answer 2

以下是使用带有304个时区的XML文件的示例。 Button1加载DGV和Button2检查以查看是否有任何更改。

Dim ds As New DataSet

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim pathToXMLFile As String = Environment.GetFolderPath( _
                                                   Environment.SpecialFolder.Desktop)
    pathToXMLFile = IO.Path.Combine(pathToXMLFile, "TimeZones.xml")
    dgv1.DataSource = Nothing
    ds.Dispose()
    ds = New DataSet
    ds.ReadXml(pathToXMLFile) 'read the xml
    'after loading all rows are 'changed'
    'set all rows to not changed
    ds.Tables(0).AcceptChanges()
    dgv1.DataSource = ds.Tables(0) 'set datagridviews datasource
End Sub

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    Dim foo As DataTable = ds.Tables(0).GetChanges
    If Not IsNothing(foo) AndAlso foo.Rows.Count > 0 Then
        'there were changes
        Debug.WriteLine(foo.Rows.Count)
        'if you are going to continue to edit
        ds.Tables(0).AcceptChanges()
    End If
End Sub

如何检查是否在DataGridView中进行了任何更改

3 个答案: