Sql Visual Basic HowTo:从.mdf检索数据

我做错了什么？我已经做了一段时间了。。。我投降

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Using sqlCon = New SqlConnection("Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\gadgetDatabase.mdf;Integrated Security=True")

        Dim Id As Integer = 2
        'With the use of ID, it will get the appName or Application Display Name
        sqlCon.Open()
        Dim sqlText = "SELECT appName " & _
                      "FROM appTable " & _
                      "WHERE Id = @sqlID"
        Dim sqlCmd = New SqlCommand(sqlText, sqlCon)
        sqlCmd.Parameters.AddWithValue("@sqlID", Id)
        'sqlCmd.ToString()
        sqlCmd.ExecuteScalar() 'I had these in there before I copied the code over
        sqlCon.Close()
        Label3.Text = sqlText 'For testing or confirmation it went correctly...

    End Using

End Sub

你忘了打电话了

string apName = sqlCmd.ExecuteScaler();

并检索结果

---

如果需要一个结果集（多个结果），那么调用

reader=cmd.ExecuteReader（）

并循环遍历结果。

我把它放在那里，但当我把代码带过来时，我意外地把它拿走了。。。它仍然返回SELECT语句作为标签文本，而不是APPNAME。它已被接受并向上投票。我向米奇麦道歉