C# 格式字符串包含“{”时的 String.Format 异常
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String.Format exception when format string contains "{"
提问by George2
I am using VSTS 2008 + C# + .Net 2.0. When executing the following statement, there is FormatException thrown from String.Format statement, any ideas what is wrong?
我使用的是 VSTS 2008 + C# + .Net 2.0。执行以下语句时，String.Format 语句抛出FormatException，有什么问题吗？
Here is where to get the template.html I am using. I want to format this part m={0} in template.html.
这是获取我正在使用的 template.html 的位置。我想在 template.html 中格式化这部分 m={0}。
string template = String.Empty;
using (StreamReader textFile = new StreamReader("template.html"))
{
template = textFile.ReadToEnd();
String.Format(template, "video.wmv");
}
http://www.mediafire.com/download.php?u4myvhbmmzg
http://www.mediafire.com/download.php?u4myvhbmmzg
EDIT 1:
编辑 1：
Here is the content for my template.html,
这是我的 template.html 的内容，
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<!-- saved from url=(0014)about:internet -->
<head>
<title>Silverlight Project Test Page </title>
<style type="text/css">
html, body {
height: 100%;
overflow: auto;
}
body {
padding: 0;
margin: 0;
}
#silverlightControlHost {
height: 100%;
}
</style>
<script type="text/javascript">
function onSilverlightError(sender, args) {
var appSource = "";
if (sender != null && sender != 0) {
appSource = sender.getHost().Source;
}
var errorType = args.ErrorType;
var iErrorCode = args.ErrorCode;
var errMsg = "Unhandled Error in Silverlight 2 Application " + appSource + "\n" ;
errMsg += "Code: "+ iErrorCode + " \n";
errMsg += "Category: " + errorType + " \n";
errMsg += "Message: " + args.ErrorMessage + " \n";
if (errorType == "ParserError")
{
errMsg += "File: " + args.xamlFile + " \n";
errMsg += "Line: " + args.lineNumber + " \n";
errMsg += "Position: " + args.charPosition + " \n";
}
else if (errorType == "RuntimeError")
{
if (args.lineNumber != 0)
{
errMsg += "Line: " + args.lineNumber + " \n";
errMsg += "Position: " + args.charPosition + " \n";
}
errMsg += "MethodName: " + args.methodName + " \n";
}
throw new Error(errMsg);
}
</script>
</head>
<body>
<!-- Runtime errors from Silverlight will be displayed here.
This will contain debugging information and should be removed or hidden when debugging is completed -->
<div id='errorLocation' style="font-size: small;color: Gray;"></div>
<div id="silverlightControlHost">
<object data="data:application/x-silverlight," type="application/x-silverlight-2" width="500" height="240">
<param name="source" value="ClientBin/VideoPlayer.xap"/>
<param name="onerror" value="onSilverlightError" />
<param name="background" value="white" />
<param name="initParams" value="cc=true,markers=true,m={0}" />
<a href="http://go.microsoft.com/fwlink/?LinkID=115261" style="text-decoration: none;">
<img src="http://go.microsoft.com/fwlink/?LinkId=108181" alt="Get Microsoft Silverlight" style="border-style: none"/>
</a>
</object>
<iframe style='visibility:hidden;height:0;width:0;border:0px'></iframe>
</div>
</body>
</html>
thanks in avdance, George
感谢 avdance，乔治
采纳答案by Marc Gravell
At a guess, the html contains javascript or another source of braces ({and }) which would all need doubling (to {{and }}) to be usable with string.Format. I expect a different (more obvious) token may be in order, i.e. %%FILENAME%%. Then use either regex or string.Replace.
猜测，html 包含 javascript 或其他大括号（{和}）来源，它们都需要加倍（到{{和}}）才能与string.Format. 我希望一个不同的（更明显的）令牌可能是有序的，即%%FILENAME%%. 然后使用正则表达式或string.Replace.
If you have a single tag, string.Replaceis fine; if you have lots, there are tricks with regex and MatchEvaluatorthat may be helpful - like sobut with a different regex pattern.
如果你只有一个标签，那string.Replace很好；如果你有很多，有正则表达式的技巧，MatchEvaluator这可能会有所帮助 -就像这样，但使用不同的正则表达式模式。
Update after the example html added: I would definitely use a different token; at the most basic level:
添加示例 html 后更新：我肯定会使用不同的令牌；在最基本的层面上：
<param name="initParams" value="cc=true,markers=true,m=%%FILENAME%%" />
and
和
template = template.Replace("%%FILENAME%%", "video.wmv");
回答by Frederik Gheysels
Wat are the contents of the 'template' variable ?
Wat 是“模板”变量的内容吗？
Difficult to say what 's wrong with your code, but presumably, the template variable does not contain a string which as a place-holder. (Like "this is some string {0}").
很难说您的代码有什么问题，但据推测，模板变量不包含作为占位符的字符串。（例如“这是一些字符串 {0}”）。
I think that you should make use of the tools your IDE provides: debug the code, use watches to inspect the contents of the template variable.
我认为您应该使用您的 IDE 提供的工具：调试代码、使用监视来检查模板变量的内容。
回答by Omar Kooheji
Whats in the template file?
模板文件里有什么？
if there are curly brackets that are not of the format {int} or there are more than there are arguments for the format statement, it'll throw an exception.
如果有不是格式 {int} 的大括号或者格式语句的参数多于参数，它会抛出异常。
What is the message in the exception?
异常中的消息是什么？
It's your Css thats doing it. As somoene else mentioned you'll need to doa regex replace, or a bunch of String.Replace commands in a row mark you variables with %%VARIABLE_NAME%% and use string replacement to replace them
这是你的 CSS 做的。正如其他人提到的，你需要做一个正则表达式替换，或者一堆 String.Replace 命令在一行中用 %%VARIABLE_NAME%% 标记你的变量并使用字符串替换来替换它们
回答by Matt Howells
Your template contains {and }characters which need to be escaped, otherwise they confuse String.Format. Escape them using {{and }}. Alternatively, use a different mechanism such as String.Replace.
您的模板包含{和}需要转义的字符，否则它们会混淆String.Format. 使用{{和转义它们}}。或者，使用不同的机制，例如String.Replace。
回答by codeape
string.Format() does not handle {and }in the format string. You need to replace {with {{and }with }}everywhere in your template.htmlfile. Except for the single place where you use the {0}placeholder.
string.Format() 不处理{和}格式字符串。您需要更换{与{{和}与}}无处不在的template.html文件。除了您使用{0}占位符的单个地方。
Not very elegant.
不是很优雅。
Instead, consider using a template engine. See http://csharp-source.net/open-source/template-enginesfor some suggestions.
相反，请考虑使用模板引擎。有关一些建议，请参阅http://csharp-source.net/open-source/template-engines。
The next-best solution is to use regexes (with MatchEvaluator) or string.Replace(), as suggested by other answers.
次佳解决方案是使用正则表达式（使用 MatchEvaluator）或 string.Replace()，正如其他答案所建议的那样。
Edit:
编辑：
Here's an example using the StringTemplate template engine:
这是使用 StringTemplate 模板引擎的示例：
StringTemplate htmlpage = new StringTemplate(File.ReadAllText("template.html"));
htmlpage.SetAttribute("content", "video.wmv");
Console.WriteLine(htmlpage.ToString());
Change a single line in your template.htmlfile:
更改template.html文件中的一行：
from:
从：
<param name="initParams" value="cc=true,markers=true,m={0}" />
to:
到：
<param name="initParams" value="cc=true,markers=true,m=$content$" />
When the template engine encounters $content$in the template, it replaces it with the value of the 'content' attribute that you set using code.
当模板引擎$content$在模板中遇到时，它会将其替换为您使用代码设置的“内容”属性的值。
Using StringTemplate, you can do simple looping and conditionals within your template. See the documentation.
使用 StringTemplate，您可以在模板中执行简单的循环和条件语句。请参阅文档。
