How to send "{}" in SendKeys

Question

I am trying to send "{" and "}" using SendKeys.Send()

I already tried to use string.Replace{"{", "{{}"}

txt = txt.Replace("{", "{{}");
txt = txt.Replace("}", "{}}");
SendKeys.Send(txt);

I expected it to send "{" and "}" but the Program throws an error

System.FormatException

Answer 1

It is quite clearly documented on the official docs

Here the relevant bit:

The plus sign (+), caret (^), percent sign (%), tilde (~), and parentheses () have special meanings to SendKeys. To specify one of these characters, enclose it within braces ({}). For example, to specify the plus sign, use "{+}". To specify brace characters, use "{{}" and "{}}". Brackets ([ ]) have no special meaning to SendKeys, but you must enclose them in braces.

The problem with your solution is that you make 2 separate replacements.

Take the input string "{".

txt = txt.Replace("{", "{{}"); // input becomes "{{}"
txt = txt.Replace("}", "{}}"); // input becomes "{{{}}"
SendKeys.Send(txt);            // error!

I'm pretty sure there is some solution more elegant than this, but you could try something like:

var sb = new StringBuilder(txt.Length);
for(var i = 0; i < txt.Length; i++)
{
    var c = txt[i];
    switch (c)
    {
      case '+':
      case '^':
      case '%':
      case '~':
      case '(':
      case ')':
      case '[':
      case ']':
      case '{':
      case '}':
        sb.Append('{');
        sb.Append(c);
        sb.Append('}');
        break;
      default:
        sb.Append(c);
        break;
    }
}
SendKeys.Send(sb.ToString());

Edit extended the escaping with a switch and a for to account for the other escapable chars.

Answer 2

As others have pointed out your second Replace, replaces the curly braces added by your first Replace.

To escape the curly braces within a string you could use Regex like this: SendKeys.Send(Regex.Replace(txt, @"[/{/}]", m => string.Format("{{{0}}}", m.Value)));

Or even better escape all characters that have special meaning in this context ie. Regex.Replace(txt, @"[/{/}/+/%/~/(/)]", m => string.Format("{{{0}}}", m.Value))

Another completely different option would be to send characters one at the time and escape curly braces when necessary:

"some{}text".ToCharArray().ToList()
   .ForEach(a=> SendKeys.Send(a == '}' || a == '{' ? "{"+a+"}": a.ToString()));

Answer 3

{ has to be escaped by {{}. } has to be escaped by {}}. This attempt to escape ...

// NON-WORKING EXAMPLE!
txt = txt.Replace("{", "{{}");
txt = txt.Replace("}", "{}}");

... has the problem, that right braces introduced by the first Replace are escaped again by the second replace. So starting from { you get

{  -->  {{}  -->  {{{}}

which is wrong. To avoid escaping braces introduced precisely as escapes, use a surrogate character for the closing escape brace in the first Replace. E.g. some Chinese character 閉, assuming that you will never want to send this character.

txt = txt.Replace("{", "{{閉");
txt = txt.Replace("}", "{}}");
// After having done the escape, replace the surrogate by the closing brace again.
txt = txt.Replace("閉", "}");

If it is not sure whether a single character will never be sent, use a improbable character sequence as surrogate, possibly from different alphabets like 閉©ξ (Chinese, Latin punctuation, Greek).

Answer 4

I would do it using a different variable to hold the entire string:

var txt = "asdf{}Asdf";
            var newString = new StringBuilder();
            for (int i = 0; i < txt.Length; i++)
            {
                if (txt[i] == '{')
                    newString.Append("{{}");
                else if(txt[i] == '}')
                    newString.Append("{}}");
                else
                    newString.Append(txt[i]);
            } 
            SendKeys.Send(newString.ToString());