Question

我正在尝试根据ToolStripComboBox中的选择来填充TableAdapter。首先，我想通过将ToolStipComboBox绑定到数据源来填充它。然后一旦填充，我想填充TableAdapter。

这是我的代码：

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（如果我单步执行代码），代码会从设置数据源的位置跳转到填充TableAdapter的位置。这导致异常，因为TableAdapter的select查询正在查找基于从ToolStipComboBox中选择的值的值。

Answer 1

我怀疑你的代码跳转到填充TableAdapter的位置，因为通过设置ComboBox的DataSource，你导致SelectedIndexChanged事件被触发。

因此，如果尚未填充ToolStripComboBox，则需要告诉SelectedIndexChanged处理程序返回，您可以通过在填充ToolStripComboBox时设置布尔标志来执行此操作。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

从Bound ToolStripComboBox填充TableAdapter

1 个答案: