从组合框中获取所选项目

Question

我有一个组合框，其中包含数据表中的项目，ff 在表单加载时执行：

dbConnection = New SqlCeConnection("Data Source=Journal.sdf")
dbDataAdapter = New SqlCeDataAdapter("SELECT * FROM setting_unit", dbConnection)
dbDataAdapter.Fill(dbTable)
cbxSettingsUnit.DataSource = New BindingSource(dbTable, Nothing)
cbxSettingsUnit.DisplayMember = "name"
cbxSettingsUnit.ValueMember = "name"

组合框有变化时的方法：

Private Sub cbxSettingsUnit_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbxSettingsUnit.SelectedIndexChanged
   tempString = cbxSettingsBusinessUnit.Items(cbxSettingsBusinessUnit.SelectedItem).ToString
   MessageBox.Show(tempString)
End Sub

该行有错误：

tempString = cbxSettingsBusinessUnit.Items(cbxSettingsBusinessUnit.SelectedItem).ToString

如何从组合框中获取所选项目？

Answer 1

大多数拥有 DataSource 属性的 .net

“listing-controls”

都会搜索 IListSource 的实现。因此，如果您将

DataTable

设置为数据源，则实际上是将

DataTable.DefaultView

设置为数据源。

Me.ComboBox1.DataSource = myDataTabele

等于

Me.ComboBox1.DataSource = myDataTabele.DefaultView

现在你有了一个包含

DataRowView

类型项目的组合框。

Dim selectedRowView As DataRowView = DirectCast(Me.ComboBox1.SelectedItem, DataRowView)
Dim selectedDisplayMemberValue As String = Me.ComboBox1.SelectedText
Dim selectValueMemberValue As Object = Me.ComboBox1.SelectedValue

你应该这样做：

Private Sub cbxSettingsUnit_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbxSettingsUnit.SelectedIndexChanged
    Dim item As DataRowView = TryCast(Me.cbxSettingsUnit.SelectedItem, DataRowView)
    If (Not item Is Nothing) Then
        With item.Row
            'You have now access to the row of your table.
            Dim columnValue1 As String = .Item("MyColumnName1").ToString()
            Dim columnValue2 As String = .Item("MyColumnName2").ToString()
        End With
    End If
End Sub

那么为什么会出现错误呢？是的，您正在尝试将 DataRowView 转换为 Integer。

'                                                                      |
tempString = cbxSettingsBusinessUnit.Items(cbxSettingsBusinessUnit.SelectedItem).ToString

Answer 2

试试这个：

Dim row_v As DataRowView = comboBox1.SelectedItem
        Dim row As DataRow = row_v.Row
        Dim itemName As String = row(0).ToString()

Answer 3

你必须使用这个

tempString = cbxSettingsUnit.Items(cbxSettingsUnit.SelectedIndex).ToString

Answer 4

尝试使用下面的代码

Try
        DS = New DataSet
        Tabel = "SELECT * FROM setting_unit"
        Dim CB As New OleDb.OleDbDataAdapter(Tabel, dbConnection)
        CB.Fill(DS, "setting_unit")
    '
        Me.cbxSettingsUnit.DataSource = Prf.Tables(0)

        Me.cbxSettingsUnit.ValueMember = "name"
        Me.cbxSettingsUnit.DisplayMember = "name"
    Catch ex As Exception
    End Try

Answer 5

tempString = cbxSettingsUnit(cbxSettingsUnit.SelectedIndex).Itemdata

Answer 6

试试这个：

combo.datasource = datatable
combo.displaymember = "abbreviation"
combo.valuemember = "abbreviation"

然后使用以下命令获取所选项目：

在组合框的 SelectionChangeCommissed 事件上放置以下内容：

    tmpString=combo.selectedvalue
    msgBox(tmpString)