Question

我尝试在.net中使用regexp来查找和替换某些令牌的字符串，例如

myString =“这是我要更改的文字示例＆lt;＃somevalue＃＆gt;和＆lt; #othervalue＃＆gt;”

如何在“＆lt;＃”和“＃＆gt;”之间找到包含令牌的文字并为每一个，做一些事情来替换它（搜索数据库并替换任何找到的匹配）？

我想要的结果：

myString =“这是我的文字示例，我想更改someValueFromDb和anotherValueFromDb”

感谢。

Answer 1

下面是一个使用Regex.Replace的示例，该示例使用MatchEvaluator通过在字典中检入指定的令牌来执行替换。如果字典中没有令牌，则文本保持不变。

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;

namespace TokenReplacement
{
    class Program
    {
        static void Main(string[] args)
        {
            string text = "this is a example of my text that I want to change <#somevalue#> and <#anothervalue#>";

            var tokens = new Dictionary<string, string>
            {
                { "somevalue", "Foo" },
                { "anothervalue", "Bar" }
            };

            Console.WriteLine(Replace(text, tokens));
        }

        static string Replace(string input, Dictionary<string, string> tokens)
        {
            MatchEvaluator evaluator = match =>
            {
                string token;
                if (tokens.TryGetValue(match.Groups[1].Value, out token))
                    return token;

                return match.Value;
            };

            return Regex.Replace(input, "<#(.*?)#>", evaluator);
        }
    }
}

Answer 2

您想要使用接受MatchEvaluator委托的Regex.Replace方法。此委托将允许您动态提供替换文本。

Regex.Replace(yourString, @"\<\#([^#]+)\#\>", delegate(Match match)
    {
       // Your code here - use match.ToString()
       // to get the matched string
    });

Answer 3

感谢所有回复，我在Replace tokens in an aspx page on load找到了答案，这正是我需要的答案

感谢指向正确方向的链接和示例。

private string ParseTagsFromPage(string pageContent)
    {
        string regexPattern = "{zeus:(.*?)}"; //matches {zeus:anytagname}
        string tagName = "";
        string fieldName = "";
        string replacement = "";
        MatchCollection tagMatches = Regex.Matches(pageContent, regexPattern);
        foreach (Match match in tagMatches)
        {
            tagName = match.ToString();
            fieldName = tagName.Replace("{zeus:", "").Replace("}", "");
            //get data based on my found field name, using some other function call
            replacement = GetFieldValue(fieldName); 
            pageContent = pageContent.Replace(tagName, replacement);
        }
        return pageContent;
    }

Answer 4

解决方案1 

这里有一个相当彻底的基于正则表达式的令牌替换和文档：

http://www.simple-talk.com/dotnet/asp.net/regular-expression-based-token-replacement-in-asp.net/

解决方案2

如果您不想添加那么多代码，这是另一种方法。此代码在配置文件AppSettings部分中查找标记（格式为＃MyName＃）我在另一个项目中使用了类似的方法在资源和数据库中查找它们（或者在特定优先级中查找所有3个）。如果您愿意，可以通过更改正则表达式和字符串替换行来更改标记的格式。

当然，通过在整个过程中使用正则表达式，仍然可以调整以获得更好的性能。

Public Shared Function ProcessConfigurationTokens(ByVal Source As String) As String
    Dim page As Page = CType(Context.Handler, Page)
    Dim tokens() As String = GetConfigurationTokens(Source)
    Dim configurationName As String = ""
    Dim configurationValue As String = ""

    For Each token As String In tokens
        'Strip off the # signs
        configurationName = token.Replace("#"c, "")

        'Lookup the value in the configuration (if any)
        configurationValue = ConfigurationManager.AppSettings(configurationName)

        If configurationValue.Contains(".aspx") OrElse configurationValue.Contains("/") Then
            Try
                Source = Source.Replace(token, page.ResolveUrl(configurationValue))
            Catch
                Source = Source.Replace(token, configurationValue)
            End Try
        Else
            'This is an optimization - if the content doesn't contain
            'a forward slash we know it is not a url.
            Source = Source.Replace(token, configurationValue)
        End If
    Next

    Return Source
End Function

Private Shared Function GetConfigurationTokens(ByVal Source As String) As String()
    'Locate any words in the source that are surrounded by # symbols
    'and return the list as an array.
    Dim sc As New System.Collections.Specialized.StringCollection

    Dim r As Regex
    Dim m As Match

    If Not String.IsNullOrEmpty(Source) Then

        r = New Regex("#[^#\s]+#", RegexOptions.Compiled Or RegexOptions.IgnoreCase)
        m = r.Match(Source)
        While m.Success

            sc.Add(m.Groups(0).Value)

            m = m.NextMatch
        End While

        If Not sc.Count = 0 Then
            Dim result(sc.Count - 1) As String
            sc.CopyTo(result, 0)

            Return result
        End If
    End If

    Return New String() {}

End Function

用.net regex替换字符串中的文本

4 个答案: