Sql 我收到以下错误'；条件表达式中的数据类型不匹配'；添加数据时

我有以下错误，但我不确定为什么会出现此错误。当我尝试向数据库添加数据时，我收到此错误

条件表达式中的数据类型不匹配。

下面是我正在编写的代码。有人能帮忙吗？谢谢

 Private Sub RefreshData()
    If Not cnn.State = ConnectionState.Open Then
        'open connection
        cnn.Open()
    End If

    Dim da As New OleDb.OleDbDataAdapter("SELECT Item ID as [Item ID], " & _
                                         "Item Name as [Item Name], " & _
                                         "Item Type as [Item Type], " & _
                                         "Quantity as [Quantity], " & _
                                         "Min Shelf Stock as [Min Shelf Stock], " & _
                                         "Purchase Price as [Purchase Price], Note " & _
                                         " From Product ORDER BY Item ID", cnn)
    Dim dt As New DataTable
    'fill data to datatable 
    da.Fill(dt)

    'offer data in data table into datagridview
    Me.dgvData.DataSource = dt

    'Close the connection
    cnn.Close()
End Sub

Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
        Dim cmd As New OleDb.OleDbCommand
        If Not cnn.State = ConnectionState.Open Then
            'The line of code below opens the connection to the database if it isnt open
        cnn.Open()
        End If

    cmd.Connection = cnn
    'Check whether to add new or update
    If Me.txtItemID.Tag & "" = "" Then
        'Add new 
        'The line of coding below adds data to table
        cmd.CommandText = "INSERT INTO Product ([Item Id], [Item Name], [Item Type], [Quantity], [Min Shelf Stock], [Purchase Price], [Note]) VALUES (@id, @name, @iType, @quantity, @minshelfstock, @price, @note)"
        cmd.Parameters.AddWithValue("@id", txtItemID.Text)
        cmd.Parameters.AddWithValue("@name", txtItemName.Text)
        cmd.Parameters.AddWithValue("@iType", cboItemType.Text)
        cmd.Parameters.AddWithValue("@quantity", txtQuantity.Text)
        cmd.Parameters.AddWithValue("@minshelfstock", txtMinShelfStock.Text)
        cmd.Parameters.AddWithValue("@price", txtPurchasePrice.Text)
        cmd.Parameters.AddWithValue("@note", txtNote.Text)
        cmd.ExecuteNonQuery()
    Else
        'Update data in the table 
        cmd.CommandText = "UPDATE Product " & _
                    " SET [Item ID]=" & Me.txtItemID.Text & _
                    ", [Item Name]='" & Me.txtItemName.Text & "'" & _
                    ", [Item Type]='" & Me.cboItemType.Text & "'" & _
                    ", [Quantity]=" & Me.txtQuantity.Text & "" & _
                    ", [Min Shelf Stock]=" & Me.txtMinShelfStock.Text & "" & _
                    ", [Purchase Price]=" & Me.txtPurchasePrice.Text & "" & _
                    ", [Note]='" & Me.txtNote.Text & "'" & _
                    " WHERE [Item ID]=" & Me.txtItemID.Tag
        cmd.ExecuteNonQuery()
    End If
    'Refresh data in list
    RefreshData()
    'Clear the form
    Me.btnClear.PerformClick()

    'The code below closes the connection to the database
    cnn.Close()
End Sub

Private Sub Product_Load(sender As Object, e As EventArgs) Handles Me.Load
    cnn = New OleDb.OleDbConnection
    cnn.ConnectionString = "Provider=Microsoft.Jet.Oledb.4.0; Data Source=" & Application.StartupPath & "\inventorysystem.mdb"
    '
    'Get the data into a list
    Me.RefreshData()
End Sub

Private Sub btnEdit_Click(sender As Object, e As EventArgs) Handles btnEdit.Click
    'check for the selected item in list
    If Me.dgvData.Rows.Count > 0 Then
        If Me.dgvData.SelectedRows.Count > 0 Then
            Dim intItemID As Integer = Me.dgvData.SelectedRows(0).Cells("Item ID").Value
            'Get the data from database followed Item ID
            'Open the connection
            If Not cnn.State = ConnectionState.Open Then
                cnn.Open()
            End If
            'Get the data into the datatable
            Dim da As New OleDb.OleDbDataAdapter("SELECT * FROM Product " & _
                                                  " WHERE Item ID=" & intItemID, cnn)
            Dim dt As New DataTable
            da.Fill(dt)

            Me.txtItemID.Text = intItemID
            Me.txtItemName.Text = dt.Rows(0).Item("Item Name")
            Me.cboItemType.Text = dt.Rows(0).Item("Item Type")
            Me.txtQuantity.Text = dt.Rows(0).Item("Quantity")
            Me.txtMinShelfStock.Text = dt.Rows(0).Item("Min Shelf Stock")
            Me.txtPurchasePrice.Text = dt.Rows(0).Item("Purchase Price")
            Me.txtNote.Text = dt.Rows(0).Item("Note")
            '
            'Hide the ID to be edited in TAG od txtItemID in case ID is changed 
            Me.txtItemID.Tag = intItemID
            'Change the add button to update 
            Me.btnAdd.Text = "Update"
            'Disable the Edit button
            Me.btnEdit.Enabled = False
            'Close the connection
            cnn.Close()
        End If
    End If
End Sub

Private Sub btnDelete_Click(sender As Object, e As EventArgs) Handles btnDelete.Click
    'Check for the selected item in the list
    If Me.dgvData.Rows.Count > 0 Then
        If Me.dgvData.SelectedRows.Count > 0 Then
            Dim intItemID As Integer = Me.dgvData.SelectedRows(0).Cells("Item ID").Value
            'Open the connection 
            If Not cnn.State = ConnectionState.Open Then
                cnn.Open()
            End If

            'Delete data 
            Dim cmd As New OleDb.OleDbCommand
            cmd.Connection = cnn
            cmd.CommandText = "DELETE FROM Product WHERE Item ID" & intItemID
            cmd.ExecuteNonQuery()
            'Refresh the data 
            Me.RefreshData()

            'Close the connection
            cnn.Close()
        End If
    End If
End Sub

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最终类

可能是由于数量数据类型造成的

试一试

不确定这是否是你想要达到的目标。

问题在于方法。此方法创建参数及其数据类型。但是，要这样做，它会查看作为第二个参数传递的值的数据类型。如果该值是一个字符串（就像您总是传递文本框的Text属性那样），那么它将生成一个类型或类似的参数。当然，对于要更新的一个或多个字段，这不是数据库所期望的

您需要检查字段的数据类型，并传递类似数据类型的参数，对文本框的字符串值应用转换

例如，如果price字段的类型为numeric decimal，则需要写入

cmd.Parameters.AddWithValue("@price", Convert.ToDecimal(txtPurchasePrice.Text))

---

跳出页面的第一件事是项目ID、项目名称等的别名。您使用的是什么数据库？我是否能够像使用MS Access一样使用它，由于您只添加了要传递给命令的值的类型。它给了我一个错误“预期语句结束”。您能调试函数并查看它在哪里弹出错误消息吗？数据类型是：项目ID=编号，项目名称=文本，项目类型=文本，数量=编号，最小货架库存=编号，采购价格=货币，注意=Text，然后您需要将这些字段的文本框值转换为相应的数值。由于我不熟悉vb，请您为此编写代码，只需使用convert.ToInt32（textbox.Text）在access和Convert中整数/长型数字字段的参数值周围。对于十进制或Convert类型的数字字段，使用ToDecimal。对于双精度或Convert类型的数字字段，使用ToDouble。对于单精度类型的数字字段，使用ToSingle。出现以下错误：输入字符串的格式不正确

cmd.Parameters.AddWithValue("@price", Convert.ToDecimal(txtPurchasePrice.Text))