Question

我有一个名为ItemsPricesTbl的表：

ItemID
FirstUnitWholeSalePrice
FirstUnitShopperPrice
FirstUnitDemotionsPrice
FirstUnitPriceDefault
SecondUnitWholeSalePrice
SecondUnitShopperPrice
SecondUnitDemotionsPrice
SecondUnitPriceDefault
ThirdUnitWholeSalePrice
ThirdUnitShopperPrice
ThirdUnitDemotionsPrice
ThirdUnitPriceDefault
DefaultPrice

获取数据的存储过程是：

ALTER PROCEDURE [dbo].[Get_Prices_Item_By_ID]
    @ItemID int
AS
BEGIN 
    SELECT
        ItemID, FirstUnitWholeSalePrice, FirstUnitShopperPrice, 
        FirstUnitDemotionsPrice, FirstUnitPriceDefault,
        SecondUnitWholeSalePrice, SecondUnitShopperPrice,
        SecondUnitDemotionsPrice, SecondUnitPriceDefault,
        ThirdUnitWholeSalePrice, ThirdUnitShopperPrice,
        ThirdUnitDemotionsPrice, ThirdUnitPriceDefault,
        DefaultPrice 
    FROM
        ItemsPricesTbl 
    WHERE
        ItemID = @ItemID
END

在Vb中我有一个DatabaseManager类，其中包含以下代码：

Private Function exeReader(ByRef cmd As SqlCommand, ByRef dr As SqlDataReader) As Integer
        Dim retval As Integer = -1
        cmd.Connection = Me.Connection
        Try
            If cmd.CommandType = CommandType.StoredProcedure Then
                Dim pr As New SqlParameter("@retval", SqlDbType.Int)
                pr.Direction = ParameterDirection.ReturnValue
                cmd.Parameters.Add(pr)
            End If
            If cmd.Connection.State = ConnectionState.Closed Then cmd.Connection.Open()
            dr = cmd.ExecuteReader()

            If cmd.CommandType = CommandType.StoredProcedure Then retval = cmd.Parameters("@retval").Value
        Catch ex As Exception
            Throw New Exception(ex.Message)
        Finally
            Me.close()
        End Try

        Return retval
    End Function

我还有两个类：数据类和业务类。

数据类代码：

Friend Sub Get_Prices_Item_By_ID(ByRef dt As DataTable, ByVal ItemID As Integer)
    Dim cmd As New SqlCommand("Get_Prices_Item_By_ID")
    cmd.Parameters.Add("@ItemID", SqlDbType.Int).Value = ItemID
    dm.fillTable(cmd, dt)
End Sub

商业类代码：

Public Function Get_Prices_Item_By_ID(ByVal ItemID As Integer) As DataTable
    Dim dt As New DataTable
    p.Get_Prices_Item_By_ID(dt, ItemID)
    Return dt
End Function

我必须在搜索按钮中输入什么代码？

我试过这个：

p.Get_Item_By_ID(FrmManage_Items.txtitemid.Text)
                FrmManage_Items.txtwholesaleone.Text = dt.Rows.ToString
                FrmManage_Items.txtcustomerone.Text = dt.Rows.ToString
                FrmManage_Items.txtsaleone.Text = dt.Rows.ToString
                FrmManage_Items.RadioButton4.Checked = dt.Rows.ToString
                FrmManage_Items.txtwholesaletwo.Text = dt.Rows.ToString
                FrmManage_Items.txtcustomertwo.Text = dt.Rows.ToString
                FrmManage_Items.txtsaletwo.Text = dt.Rows.ToString
                FrmManage_Items.RadioButton5.Checked = dt.Rows.ToString
                FrmManage_Items.txtwholesalethird.Text = dt.Rows.ToString
                FrmManage_Items.txtcustomerthird.Text = dt.Rows.ToString
                FrmManage_Items.txtsalethird.Text = dt.Rows.ToString
                FrmManage_Items.RadioButton6.Checked = dt.Rows.ToString
                FrmManage_Items.TextBox20.Text = dt.Rows.ToString

但我没有得到记录 - 但是我在每个文本框中得到的错误：

System.Data.DataRowCollection

注意：连接位于app.config文件

中

Answer 1

你ToString Rows（所有这些），而不是连续的数据。当您在ToString上致电DataRowCollection时，它会为您提供“System.Data.DataRowCollection”。

您需要在与文本框匹配的行和列索引中提取数据。您的文本框名称与列名称不匹配，但做出假设，请执行以下操作：

FrmManage_Items.txtwholesaleone.Text = dt.Rows(0)("FirstUnitWholeSalePrice").ToString
FrmManage_Items.txtcustomerone.Text = dt.Rows(0)("FirstUnitShopperPrice").ToString
'etc....

当然，您应该检查实际上至少有一行返回，并且没有任何列值为空，因为如果列为ToString，则无法调用DBNull.Value。

另外，没有理由传递参数ByRef。这是一个完全不同的讨论，但它是错误的，除非你真的打算更改对象的引用（而不是它的值或属性，它的引用）。

我还建议您在方法中创建命令和连接，这样您就可以确保Dispose()它们（以及数据适配器），因为它们是可支配的资源。要么你或你的班级需要实施IDisposable，那就更复杂了。

Answer 2

我写了错误的方法代码

它不是读者

它是：

Public Function fillTable(ByRef cmd As SqlCommand, ByRef dt As DataTable) As Integer
    Dim retval As Integer = -1
    dt = New DataTable
    cmd.CommandType = CommandType.StoredProcedure
    cmd.Connection = Me.Connection
    Dim da As New SqlDataAdapter(cmd)
    da.Fill(dt)

    If (Not dt Is Nothing) Then retval = dt.Rows.Count
    Return retval
End Function

按钮的代码是：

p.Get_Prices_Item_By_ID(FrmManage_Items.txtitemid.Text)
                FrmManage_Items.txtwholesaleone.Text = dt.Rows.ToString
                FrmManage_Items.txtcustomerone.Text = dt.Rows.ToString
                FrmManage_Items.txtsaleone.Text = dt.Rows.ToString
                FrmManage_Items.RadioButton4.Checked = dt.Rows.ToString
                FrmManage_Items.txtwholesaletwo.Text = dt.Rows.ToString
                FrmManage_Items.txtcustomertwo.Text = dt.Rows.ToString
                FrmManage_Items.txtsaletwo.Text = dt.Rows.ToString
                FrmManage_Items.RadioButton5.Checked = dt.Rows.ToString
                FrmManage_Items.txtwholesalethird.Text = dt.Rows.ToString
                FrmManage_Items.txtcustomerthird.Text = dt.Rows.ToString
                FrmManage_Items.txtsalethird.Text = dt.Rows.ToString
                FrmManage_Items.RadioButton6.Checked = dt.Rows.ToString
                FrmManage_Items.TextBox20.Text = dt.Rows.ToString

我想在txtitemid.text

中输入item的id

它将搜索此ID并返回记录的其余部分（如果找到）

FirstUnitWholeSalePrice.text
FirstUnitShopperPrice.text
FirstUnitDemotionsPrice.text
FirstUnitPriceDefault.text
SecondUnitWholeSalePrice.text
SecondUnitShopperPrice.text
SecondUnitDemotionsPrice.text
SecondUnitPriceDefault.text
ThirdUnitWholeSalePrice.text
ThirdUnitShopperPrice.text
ThirdUnitDemotionsPrice.text
ThirdUnitPriceDefault.text
DefaultPrice.text

如何通过存储过程在文本框中显示来自SQL Server的记录

2 个答案: