Question

我有一些C＃代码要添加到现有的VB.net项目中。 C＃类被设计为html解析器

最初使用过在线转换器并且能够让大部分课程正常工作，但下面的部分仍无法正常工作。不幸的是，我缺乏解决这个问题的知识。

我发布了整篇文章，但如果有人能澄清前两行，我认为这就足够了。 AttributeNameValuePair是一个包含属性的独立类。

进一步使用一些内联函数，也会欣赏它的一个例子。或者将这些作为单独的函数并且仅在内部留下引用会更容易吗？

事先感谢您的帮助。

            private readonly Dictionary<string, Action<DocumentModel, IEnumerable<AttributeNameValuePair>>> commandsDictionary = new Dictionary<string, Action<DocumentModel, IEnumerable<AttributeNameValuePair>>>()
    {
        { "b", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => GetLastRun(doc).CharacterFormat.Bold = true) },
        { "i", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => GetLastRun(doc).CharacterFormat.Italic = true) },
        { "u", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => GetLastRun(doc).CharacterFormat.UnderlineStyle = UnderlineType.Single) },
        { "strike", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => GetLastRun(doc).CharacterFormat.Strikethrough = true) },
        { "sub", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => GetLastRun(doc).CharacterFormat.Subscript = true) },
        { "sup", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => GetLastRun(doc).CharacterFormat.Superscript = true) },
        { "div", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => 
            {
              foreach(var arg in args)
              {
                  if(arg.AttributeName == "align")
                  {
                      HorizontalAlignment align;
                      switch(arg.AttributeValue)
                      {
                          case "center":
                              align = HorizontalAlignment.Center;
                              break;
                          case "right":
                              align = HorizontalAlignment.Right;
                              break;
                          case "justify":
                              align = HorizontalAlignment.Justify;
                              break;
                          default:
                              align = HorizontalAlignment.Left;
                              break;
                      }
                  }
              }
            })},
        { "br", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => doc.Sections[0].Blocks.Add(new Paragraph(doc))) },
        {  "span",  new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => {})},
        { "font", new Action<DocumentModel, IEnumerable<AttributeNameValuePair>>((doc, args) => 
            {
                foreach(AttributeNameValuePair arg in args)
                {
                    int? size = null;
                    string fontName = null;

                    // Some dummy values.
                    if (arg.AttributeName == "size")
                        size = 10 + 3 * int.Parse(arg.AttributeValue);
                    else if (arg.AttributeName == "face")
                        fontName = arg.AttributeValue.Split(',').First();

                    var lastFormat = GetLastRun(doc).CharacterFormat;
                    if (size.HasValue)
                        lastFormat.Size = size.Value;

                    if (fontName != null)
                        lastFormat.FontName = fontName;
                }
            })},
    };

Answer 1

这是哪个版本的vb.net？ Lambda表达式在每个表达式中的工作方式略有不同。多线lambda仅在VS2010 +中受支持。对于VS2008，您通常最终必须将匿名方法转换为实际方法并通过AddressOf引用它们。我注意到，自动翻译在从C＃转换匿名/ lambda类型表达式时通常似乎失败了。

在任何情况下，与C＃相比，VB中的匿名方法语法有点笨拙且不同，令人困惑。对于单行方法，您可以执行类似的操作（为清晰起见，我使用简单类型）：

Private cmdDictionary As New Dictionary(Of String, Action(Of Integer, String))

'adding items'
cmdDictionary.Add("div", New Action(Of Integer, String) _
      (Sub(x As Integer, y As String) Console.WriteLine(y & ":" & CStr(x))))

'then to access the dictionary'
cmdDictionary.Item("div")(42, "foobar")

对于多线（在vs2010中），模式如下：

cmdDictionary.Add("div", New Action(Of Integer, String) _
                        (Sub(x As Integer, y As String)
                             x = 2 * x
                             Console.WriteLine(y & ":" & CStr(x))
                         End Sub))

Answer 2

您可以将此C＃代码1：1翻译为VB.Net。

在此示例中，我仅添加了b和div，但它应该足以引导您：

Private Readonly commandsDictionary As Dictionary(Of string, Action(Of DocumentModel, IEnumerable(Of AttributeNameValuePair))) = 
new Dictionary(Of string, Action(Of DocumentModel, IEnumerable(Of AttributeNameValuePair)))() From 
{
    { "b", new Action(Of DocumentModel, IEnumerable(Of AttributeNameValuePair)) (Sub(doc, args) GetLastRun(doc).CharacterFormat.Bold = true) },
    { "div", new Action(Of DocumentModel, IEnumerable(Of AttributeNameValuePair))(Sub(doc, args)  
          For Each arg in args
              if arg.AttributeName = "align" Then
                  Dim align as HorizontalAlignment
                  Select arg.AttributeValue
                      case "center":
                          align = HorizontalAlignment.Center
                      case "right":
                          align = HorizontalAlignment.Right
                      case "justify":
                          align = HorizontalAlignment.Justify
                      case else:
                          align = HorizontalAlignment.Left
                  end select
              end if
          Next
    End Sub)}}
}

您可能想为Action(Of DocumentModel, IEnumerable(Of AttributeNameValuePair))创建一个类型别名，因为这会大大提高可读性。

C＃转VBNET转换问题

2 个答案: