vb.net VB .NET COMBOBOX ValueMember
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VB .NET COMBOBOX ValueMember
提问by Tom Konski
Hi guys I have problem with ValueMember. Look on code :
大家好，我有 ValueMember 的问题。查看代码：
conn.ConnectionString = _
"Provider=Microsoft.Jet.OLEDB.4.0;Data source=" & _
"c:\magazyn.mdb"
' Try
conn.Open()
da2 = New OleDbDataAdapter(sql1, conn)
da2.Fill(ds2)
' DataGridView1.DataSource = ds.Tables("Nazwa")
' DataGridView1.Update()
ComboBox4.DataSource = Nothing
ComboBox4.DataSource = ds2.Tables(0)
ComboBox4.ValueMember = Nothing
ComboBox4.DisplayMember = "Nazwa_Towaru"
ComboBox4.ValueMember = "Kod_Towaru"
MessageBox.Show(ComboBox4.Text + "-" + ComboBox4.ValueMember)
' Catch ex As Exception
'MessageBox.Show("Brak pod??czonej bazy/problem z pod??czeniem do bazy")
' Finally
conn.Close()
' End Try
MessageBox should show me somthing like this : Graphic Card - 123ASD first element is "Nazwa_Towaru" second is "Kod_Towaru" but MB show me somthing like this : Graphic Card - "Kod_Towaru". First time I think "Kod_Towaru" column in DATASET is empty but i check this and column is with data .
MessageBox 应该向我展示这样的东西：图形卡 - 123ASD 第一个元素是“Nazwa_Towaru”，第二个是“Kod_Towaru”，但 MB 向我展示这样的东西：显卡 - “Kod_Towaru”。我第一次认为 DATASET 中的“Kod_Towaru”列是空的，但我检查了这一列，并且该列包含数据。
I have also another ComboBox with this same code and its work great so why this one not. ALL variables are local so they no colidate.
我还有另一个具有相同代码的 ComboBox，它的工作非常好，为什么不使用这个。所有变量都是局部变量，因此它们没有共存。
回答by Serge Bollaerts
I guess that ComboBox4.SelectedIndex = -1. After binding your combo box with a data source, set the selected index to 0 (if there are data in the combo box)
我猜 ComboBox4.SelectedIndex = -1。将你的组合框与数据源绑定后，将选中的索引设置为0（如果组合框中有数据）
Serge
哔叽
