Unquote string in C#

On your string use Trim with the " as char:

.Trim('"')

I usually call String.Trim() for that purpose:

string source = "\"Hello World!\"";
string unquoted = source.Trim('"');

My implementation сheck that quotes are from both sides

public string UnquoteString(string str)
{
    if (String.IsNullOrEmpty(str))
        return str;

    int length = str.Length;
    if (length > 1 && str[0] == '\"' && str[length - 1] == '\"')
        str = str.Substring(1, length - 2);

    return str;
}