你可以使用$。

插入字符串: 用于构造字符串。插值字符串看起来像包含插值表达式的模板字符串。插值后的字符串返回一个字符串，该字符串将其包含的插值表达式替换为它们的字符串表示形式。该特性在c# 6及更高版本中可用。

string commentor = $"<span class=\"fa fa-plus\" aria-hidden=\"true\"> {variable}</span>";

你需要通过将它们加倍来转义(逐字串字面量):

string str = @"""How to add doublequotes""";

或者对于普通的字符串，你可以用\:

string str = "\"How to add doublequotes\"";

另注:

    string path = @"H:\\MOVIES\\Battel SHIP\\done-battleship-cd1.avi";
    string hh = string.Format("\"{0}\"", path);
    Process.Start(@"C:\Program Files (x86)\VideoLAN\VLC\vlc.exe ", hh + " ,--play");

hh的实际值，正如传递的那样，将是"H:\MOVIES\ batttel SHIP\done-battleship-cd1.avi"。

当需要双双字面值时，使用:@"H:\MOVIES\ batttel SHIP\done-battleship-cd1.avi";

而不是:@"H:\ moviesbatttel SHIP\done-battleship-cd1.avi";

因为第一个字面值是路径名，第二个字面值是双引号。

所以你本质上是问如何存储双引号在一个字符串变量?有两个解决方案:

var string1 = @"""inside quotes""";
var string2 = "\"inside quotes\"";

为了让大家更清楚发生了什么:

var string1 = @"before ""inside"" after";
var string2 = "before \"inside\" after";

在c# 11.0预览版中，你可以使用原始字符串字面值。

Raw string literals are a new format for string literals. Raw string literals can contain arbitrary text, including whitespace, new lines, embedded quotes, and other special characters without requiring escape sequences. A raw string literal starts with at least three double-quote (""") characters. It ends with the same number of double-quote characters. Typically, a raw string literal uses three double quotes on a single line to start the string, and three double quotes on a separate line to end the string.

string str = """
    "How to add double quotes"
    """;

使用工作示例的字符串插值:

var title = "Title between quotes";
var string1 = $@"<div>""{title}""</div>";  // Note the order of the $@
Console.WriteLine (string1);

输出

<div>"Title between quotes"</div>