从绑定TableAdapter填充ToolStripComboBox

Question

我正在尝试根据从TableAdapter中选择的内容来填充ToolStripComboBox。首先，我希望通过将ToolStipComboBox绑定到数据源来填充它。然后，一旦它被填充，我想填充TableAdapter。

这是我的密码：

Private Sub ToolStripComboBox_MessageType_Click(sender As Object, e As EventArgs) Handles ToolStripComboBox_MessageType.Click
    Me.ToolStripComboBox_MessageType.ComboBox.DataSource = DataSet_UToolDb.XML_MESSAGE_TYPE
    Me.ToolStripComboBox_MessageType.ComboBox.DisplayMember = "MessageType"
    Me.ToolStripComboBox_MessageType.ComboBox.ValueMember = "MTId"
End Sub

Private Sub ToolStripComboBox_MessageType_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ToolStripComboBox_MessageType.SelectedIndexChanged
    Me.TableAdapter_XML_MESSAGE_STRUCTURE.Fill(DataSet_UToolDb.XML_MESSAGE_STRUCTURE, Me.ToolStripComboBox_MessageType.ComboBox.SelectedValue)
End Sub

由于某种原因(如果我执行我的代码)，代码从设置数据源的位置跳到填充TableAdapter的位置。这会导致异常，因为TableAdapter的select查询根据从ToolStipComboBox中选择的值寻找一个值。

Answer 1

我怀疑您的代码正在跳到填充TableAdapter的位置，因为通过设置ComboBox的DataSource，您将触发SelectedIndexChanged事件。

因此，您需要告诉SelectedIndexChanged处理程序在尚未填充ToolStripComboBox时返回，这可以通过在填充了ToolStripComboBox时设置一个布尔标志来实现。例如：

Dim m_ToolStripComboBoxPopulated As Boolean

Private Sub ToolStripComboBox_MessageType_Click(sender As Object, e As EventArgs) Handles ToolStripComboBox_MessageType.Click
    Me.m_ToolStripComboBoxPopulated = False
    Me.ToolStripComboBox_MessageType.ComboBox.DataSource = DataSet_UToolDb.XML_MESSAGE_TYPE
    Me.ToolStripComboBox_MessageType.ComboBox.DisplayMember = "MessageType"
    Me.ToolStripComboBox_MessageType.ComboBox.ValueMember = "MTId"
    ' Indicate ToolStripComboBox has been populated
    Me.m_ToolStripComboBoxPopulated = True
End Sub

Private Sub ToolStripComboBox_MessageType_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ToolStripComboBox_MessageType.SelectedIndexChanged
    If (Me.m_ToolStripComboBoxPopulated = False) Then
        Return
    End If
    Me.TableAdapter_XML_MESSAGE_STRUCTURE.Fill(DataSet_UToolDb.XML_MESSAGE_STRUCTURE, Me.ToolStripComboBox_MessageType.ComboBox.SelectedValue)
End Sub