Question

美好的一天。我正在尝试将数据从数据表显示到文本框控件。但是当程序运行时，我无法按下计算按钮。在此之前，我已尝试在datagridview控件上显示数据并显示。有没有人可以帮助我？非常感谢。

    provider = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source ="
    dataFile = "C:\Users\User\Documents\SharkRay Database.accdb"
    connString = provider & dataFile
    myConnection.ConnectionString = connString
    myConnection.Open()

    Dim da As OleDbDataAdapter = New OleDbDataAdapter("Select Sum([Shark Individual Weight]) From FishCaught Where [OperationID] =" & TextBoxOpID4.Text & " and [Scientific Name] ='" & ComboBoxSpeciesName2.SelectedItem & "'", myConnection)

    Dim ds As DataTable = New DataTable()
    da.Fill(ds)

    TextBoxAllSharkTW.Text = ds.ToString()

    myConnection.Close()

Answer 1

试试这段代码。

 provider = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source ="
    dataFile = "C:\Users\User\Documents\SharkRay Database.accdb"
    connString = provider & dataFile
    myConnection.ConnectionString = connString
    myConnection.Open()

               Dim cmd As New OleDb.OleDbCommand("Select Sum([Shark Individual Weight]) From FishCaught Where [OperationID] =" & TextBoxOpID4.Text & " and [Scientific Name] ='" & ComboBoxSpeciesName2.SelectedItem & "'", myConnection)
        Dim count As Int32 = CInt(cmd.ExecuteScalar)

        TextBoxAllSharkTW.Text = cstr(count)
 myConnection.Close()

Answer 2

    Dim cmd As New OleDbCommand("Select Sum([Shark Individual Weight]) From    FishCaught Where [OperationID] =" & TextBoxOpID4.Text & " and [Scientific Name] ='" & ComboBoxSpeciesName2.SelectedItem & "'", myConnection)
    Dim count As Integer = cmd.ExecuteScalar()

    TextBoxSharkTWbySpecies.Text = count.ToString()
    cmd.Dispose()
    myConnection.Close()

我对Shadow Fiend给出的代码做了一些修改，最后它有效！感谢。

如何在文本框中的数据表中显示数据？ vb.net

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