从所选项目组合框中取回值 [英] Take back the value from the selecteditem Combobox

问题描述

我有这个子程序来填充一些组合框

I have this subroutine to fill some comboboxes

Private Sub Fill_Combo_Box(ByVal ParmSQL As String, ByVal ComboName As ComboBox)
    Dim Con As OleDbConnection
    Dim sqlCmd As OleDbCommand = New OleDbCommand(ParmSQL)
    Con = New OleDbConnection(Main_Form.ConString)
    Try
        Con.Open()
        sqlCmd.Connection = Con
        myData = sqlCmd.ExecuteReader
        Do While myData.Read
            ComboName.ValueMember = myData.Item(0)
            ComboName.Items.Add(myData.Item(1).ToString.PadRight(10, " ") & " " & myData.Item(2))
        Loop
    Catch ''ex As OledbException
    End Try
    Con.Close()
End Sub

子例程工作很好，但是请随时帮助我如何处理
来自selecteditem的值?

谢谢，问候...

The subroutine work great but please help me how i can take at any time the
value from the selecteditem??

Thanks and regards...

推荐答案

如果您只想选择所选项目的文本，则可以使用

If you just want the text of the Item that was selected, you can use

<br />
ComboName.SelectedItem.Text;<br />

如果您需要实际值而不是文本:

if you want the actual value and not the text:

<br />
ComboName.SelectedValue;<br />

您应该在comboBox的SelectedIndexChanged事件上获取值.
我希望这是您想知道的.祝你好运，我的朋友

You should get the values on the SelectedIndexChanged Event of your comboBox.
I hope this is what you wanted to know. Good Luck my friend

好，首先，您应该使用OleDbAdapter和数据集而不是阅读器.您的代码如下所示:

Ok, first you should use OleDbAdapter and a dataset instead of the reader. Your code would look like this:

Private Sub Fill_Combo_Box(ByVal ParmSQL As String, ByVal ComboName As ComboBox)    Dim Con As OleDbConnection
Dim adapter as OleDbAdapter    
Dim dataSet as DataSet
Dim sqlCmd As OleDbCommand = New OleDbCommand(ParmSQL)    
Con = New OleDbConnection(Main_Form.ConString)    

Try        
Con.Open()        
sqlCmd.Connection = Con        
adapter.SelectCommand = sqlCmd
adapter.Fill(dataSet)

'Then we set the dataSource to the dataset's table       
ComboName.DataSource = dataSet.Tables(0)
ComboName.ValueMember = "NameOfFirstColumn"
ComboName.DisplayMember = ("NameOfSecondColumn").PadRight(10, " ") & " " & "NameOfThirdColumn"

           
Catch 'ex As OledbException    End Try    Con.Close()End Sub

我不太确定displayMember是一个有效的表达式，我猜不是，但是也许您可以在sql表中添加一个具有所需格式的文本的新列，然后您只需说:

ComboName.DisplayMember =(" NameOfNewColumnWithTheFormat)

同时，通过使用SelectedItem.Value，您可以仅使用valuemember进行测试，而不会与displayMember混淆.祝你好运

I''m not too sure about the displayMember being a valid expression, I''m guessing not but maybe you could add a new column to your sql table that has the text in the format you want and then you''d just say:

ComboName.DisplayMember = ("NameOfNewColumnWithTheFormat")

Meanwhile you can test just with the valuemember and not mess with the displayMember by using SelectedItem.Value. Good Luck

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