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我的打印预览代码不起作用。我如何使这项工作。帮助将不胜感激。谢谢你。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 ID： 职务： 姓名： Bob 地址： 汽车： 汽车 ID： 升级： 成本： 产品 ID： 商店 ID：

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：以前使用过变量“LineToPrints”，它可能导致空值。

    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
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1 回答 1

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你没有详细说明你得到了什么错误，或者它发生在哪里，但是你的格式字符串有两个占位符，你每次只传递一个参数。Dim MyFormat As String = "{0, 15}"如果您希望标签和值适合 15 个字符，或者String.Format(MyFormat, "Product ID:", OneStock.ProductID)标签和值应该在不同的列中，请考虑使用。

注意：考虑将字段元数据存储在某些数据结构中，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))
于 2013-12-22T23:42:26.543 回答