vb.net如何在标签中显示来自sql的数据

Question

我希望将我的select syntac显示为lable但我的代码没有工作这只显示1实际数据是11

Try
    If IsNothing(ds.Tables("kkpsurabaya")) = False Then
        ds.Tables("kkpsurabaya").Rows.Clear()
    End If

    query = "SELECT count(total_telat) FROM kkpsurabaya WHERE LATE <=30 And Late >=1"

    da = New SqlDataAdapter(query, conn)
    da.Fill(ds, "kkpsurabaya")

    Label7.Text = da.Fill(ds, "kkpsurabaya")

    da.Dispose()
    conn.Close()
Catch ex As Exception
    FatalErrorOccured(ex)
End Try

Answer 1

您不应该使用数据适配器和DataTable。这是获取表格结果集的方法。如果您想要单个值，请使用命令并调用ExecuteScalar。

Dim command As New SqlCommand(query, conn)

Label7.Text = command.ExecuteScalar().ToString()

要了解在什么情况下要使用的ADO.NET对象，请查看我的示例here。

Answer 2

现在解决了

    conn.Open()

    query = "SELECT count(total_telat) as total_telat FROM kkpsurabaya WHERE total_telat <=30 and total_telat >=1"
    cmd = New SqlCommand(query, conn)
    Try

        RD = cmd.ExecuteReader()
        If RD.Read() Then
            Label7.Text = RD.GetValue(0)
        End If
        RD.Close()
    Catch ex As System.Exception
        MsgBox(ex.Message)
    End Try
    conn.Close()