从变量中添加文本的多行字符串

本文关键字：字符串 文本 变量 添加 | 更新日期: 2023-09-27 18:10:55

我知道这会起作用的:

string multiline_text = @"this is a multiline text
this is line 1
this is line 2
this is line 3";

我如何使以下工作:

string a1 = " line number one";
string a2 = " line number two";
string a3 = " line number three";
string multiline_text = @"this is a multiline text
this is " + a1 + " 
this is " + a2 + " 
this is " + a3 + ";

是否有可能不将字符串分成几个子字符串，每行一个?

从变量中添加文本的多行字符串

一种选择是使用字符串格式。c# 6之前:

string pattern = @"this is a multiline text
this is {0}
this is {1}
this is {2}";
string result = string.Format(pattern, a1, a2, a3);

在c# 6中，您可以使用逐字插入的字符串字面值:

string pattern = $@"this is a multiline text
this is {a1}
this is {a2}
this is {a3}";

请注意，$@必须完全是这样-如果您尝试使用@$，它将无法编译。

虽然string.Format是更好的实践，但要做到您想要实现的目标，只需在每行末尾添加额外的@ s:

string multiline_text = @"this is a multiline text
this is " + a1 + @" 
this is " + a2 + @" 
this is " + a3 + @"";

您还缺少最后一个"在结束的分号之前。

您可以从StringBuilder类中获得这样的可读性:

StringBuilder sb = new StringBuilder();
sb.AppendLine("this is a multiline");
sb.AppendLine("this is " + a1); // etc
var result = sb.ToString();

使用c# 6 (Visual Studio 2015)，您可以编写:

string multiline_text = $@"this is a multiline text
this is {a1}
this is {a2}
this is {a3}";

字符串。格式将被编译器使用(就像在琼斯的回答中一样)，但它更容易阅读。

由于某些原因c#不支持这样的多行文本。最接近的是:

string a1 = " line number one";
string a2 = " line number two";
string a3 = " line number three";
string multiline_text = @"this is a multiline text" +
"this is " + a1 +
"this is " + a2 +
"this is " + a3;

另一个可能的解决方案与Jon Skeet的答案类似:

string result = string.Format(
    "this is a multiline text{0}this is {1}{0}this is {2}{0}this is {3}",
    Environment.NewLine, a1, a2, a3);

，所以基本上你插入一个新的行，你想一个{0}。因此，它使字符串更加抽象，但这种解决方案的好处是它完全封装在string.Format方法中。这可能不太相关，但还是值得一提。

为了好玩，您还可以使用数组连接技术来获得可读的内容并控制缩进。有时多行模板强迫你完全左对齐是不美观的…

string a1 = "London", a2 = "France", a3 = "someone's underpants";
string result = string.Join(Environment.NewLine, new[] {
    $"this is {a1}", // interpolated strings look nice
    "this is " + a2, // you can concat if you can't interpolate
    $"this is {a3}"  // these in-line comments can be nice too
});

如果必须格式化，请将连接换行以获得整洁的结果，而不是单独换行。

从c# 11和。net 7开始，可以使用支持插值的原始字符串字面值:

string a1 = " line number one";
string a2 = " line number two";
string a3 = " line number three";
string multiline_text = $"""
this is a multiline text
this is {a1} 
this is {a2}
this is {a3}
""";
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