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copied!<p>There's no such function, at least none I know of. But one method would be to use a regular expression to remove everything that is not a number:</p> <pre><code>using System; using System.Text.RegularExpressions; int result = // The Convert (System) class comes in pretty handy every time // you want to convert something. Convert.ToInt32( Regex.Replace( "12ACD", // Our input "[^0-9]", // Select everything that is not in the range of 0-9 "" // Replace that with an empty string. )); </code></pre> <p>This function will yield <code>12</code> for <code>12ABC</code>, so if you need to be able to process negative numbers, you'll need a different solution. It is also not safe, if you pass it only non-digits it will yield a <code>FormatException</code>. Here is some example data:</p> <pre><code>"12ACD" => 12 "12A5" => 125 "CA12A" => 12 "-12AD" => 12 "" => FormatException "AAAA" => FormatException </code></pre> <p>A little bit more verbose but safer approach would be to use <a href="http://msdn.microsoft.com/en-us/library/f02979c7" rel="noreferrer"><code>int.TryParse()</code></a>:</p> <pre><code>using System; using System.Text.RegularExpression; public static int ConvertToInt(String input) { // Replace everything that is no a digit. String inputCleaned = Regex.Replace(input, "[^0-9]", ""); int value = 0; // Tries to parse the int, returns false on failure. if (int.TryParse(inputCleaned, out value)) { // The result from parsing can be safely returned. return value; } return 0; // Or any other default value. } </code></pre> <p>Some example data again:</p> <pre><code>"12ACD" => 12 "12A5" => 125 "CA12A" => 12 "-12AD" => 12 "" => 0 "AAAA" => 0 </code></pre> <p>Or if you only want the <em>first</em> number in the string, basically stopping at meeting something that is not a digit, we suddenly also can treat negative numbers with ease:</p> <pre><code>using System; using System.Text.RegularExpression; public static int ConvertToInt(String input) { // Matches the first numebr with or without leading minus. Match match = Regex.Match(input, "-?[0-9]+"); if (match.Success) { // No need to TryParse here, the match has to be at least // a 1-digit number. return int.Parse(match.Value); } return 0; // Or any other default value. } </code></pre> <p>And again we test it:</p> <pre><code>"12ACD" => 12 "12A5" => 12 "CA12A" => 12 "-12AD" => -12 "" => 0 "AAAA" => 0 </code></pre> <p>Overall, if we're talking about user input I would consider not accepting invalid input at all, only using <code>int.TryParse()</code> without some additional magic and on failure informing the user that the input was suboptimal (and maybe prompting again for a valid number).</p>

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