需要帮助从文件预览vb打印记录信息

Question

我的打印预览代码不起作用。我该如何做到这一点。帮助将不胜感激。谢谢。我试图显示我的最终结帐收据，我无法粘贴图片，所以它是这样的：

客户编号：标题：姓名：鲍勃地址：汽车：汽车识别码：升级：成本：产品编号：店铺编号：

我希望这些在打印预览屏幕的列布局中。我该怎么做？

我还收到一条警告：变量"LineToPrints"以前曾使用过，它可能会导致空值。

    Dim TitleFont As New Font("Courier New", 15, FontStyle.Bold)
    Dim MyFont As New Font("Courier New", 12, FontStyle.Regular)
    Dim MyFormat As String = "{0, 15}{1,15}"
    Dim LineToPrints As String
    Dim X As Integer
    Dim Y As Integer
    X = 15
    FontHeight = MyFont.GetHeight(e.Graphics)
    e.Graphics.DrawString("Checkout Receipt", TitleFont, Brushes.Black, X, Y)
    For Y = 15 To 165 Step 15
        Select Case Y
            Case 30
                LineToPrints = String.Format(MyFormat, "Customer ID: " & OneCustomer.CustomerID)
            Case 45
                LineToPrints = String.Format(MyFormat, "Title: " & OneCustomer.Title)
            Case 60
                LineToPrints = String.Format(MyFormat, "Name: " & Trim(OneCustomer.FirstName) & Trim(OneCustomer.LastName))
            Case 75
                LineToPrints = String.Format(MyFormat, "Address: " & OneCustomer.Address)
            Case 90
                LineToPrints = String.Format(MyFormat, "Car(s): " & OneBooking.Car)
            Case 105
                LineToPrints = String.Format(MyFormat, "Car ID: " & OneBooking.CarID)
            Case 120
                LineToPrints = String.Format(MyFormat, "Upgrades: " & OneBooking.Upgrade)
            Case 135
                LineToPrints = String.Format(MyFormat, "Cost: " & FormatCurrency(TotalCost))
            Case 150
                LineToPrints = String.Format(MyFormat, "Product ID: " & OneStock.ProductID)
            Case 165
                LineToPrints = String.Format(MyFormat, "ShopID: " & OneStock.ShopID)
        End Select
        e.Graphics.DrawString(LineToPrints, TitleFont, Brushes.Black, X, Y + 10)
        e.Graphics.DrawString("Thank You For Purchasing At 'Ford Mustaang Selection Buyout'.", TitleFont, Brushes.Black, X, Y)
    Next

Answer 1

您尚未详细说明您遇到的错误或发生错误的位置，但您的格式字符串有两个占位符，并且您每次只传入一个参数。如果希望标签和值适合 15 个字符，请考虑使用 Dim MyFormat As String = "{0, 15}"，或者如果标签和值应位于单独的列中，请考虑使用 String.Format(MyFormat, "Product ID:", OneStock.ProductID)。

注意：考虑将字段元数据存储在某种数据结构中，例如 List(Of Tuple(Of String,Object)) ：

Dim metadata = New List(Of Tuple(Of String, Object)) From {
    Tuple.Create("Customer ID", OneCustomer.CustomerID),
    Tuple.Create("Title", OneCustomer.Title),
    Tuple.Create("Name", CType(Trim(OneCustomer.FirstName) & Trim(OneCustomer.LastName),Object)),
    Tuple.Create("Address", OneCustomer.Address),
    Tuple.Create("Car(s)", OneBooking.Car),
    Tuple.Create("Car ID", OneBooking.CarID),
    Tuple.Create("Upgrades", OneBooking.Upgrade),
    Tuple.Create("Cost", CType(FormatCurrency(TotalCost),Object)),
    Tuple.Create("Product ID", OneStock.ProductID),
    Tuple.Create("Shop ID", OneStock.ShopID)
}

然后，您可以生成报告的每一行，如下所示：

Dim line=String.Join("", metadata.Select(Function(t) String.Format("{0,15}: {1,15}", t.Item1, t.Item2))