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POFormattedException instead of throw new Exception(string.Format(...)) in .NET
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  1. POFormattedException instead of throw new Exception(string.Format(...)) in .NET
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    copied!<p>I have been thinking of a good generic exception object that would replace <code>throw new Exception(string.Format("...",...))</code>, to both simplify and also to speed up such objects. The formatting by slow <code>String.Format()</code> should be delayed until <code>Message</code> property is called. Serialization is also somewhat risky. Also, such object could later implement localization.</p> <p><strong>Update</strong>: This exception should be inherited by more specific user exceptions, not thrown itself. Sorry for not making this clear.</p> <p>This is what I have come up with. Please comment if there are any ways to improve it. Thanks!</p> <pre><code>/// &lt;summary&gt; /// Generic exception capable of delayed message formatting. /// Inherit for more specific exceptions. /// &lt;/summary&gt; [Serializable] public class FormattedException : Exception { private readonly object[] _arguments; private readonly string _formatStr; private readonly bool _useFormat; private FormattedException(bool useFormat, Exception inner, string message, params object[] args) : base(message, inner) { _useFormat = useFormat; _formatStr = message; _arguments = args; } public FormattedException() : this(false, null, null, null) {} public FormattedException(string message) : this(false, null, message, null) {} public FormattedException(string message, params object[] args) : this(true, null, message, args) {} public FormattedException(Exception inner, string message) : this(false, inner, message, null) {} public FormattedException(Exception inner, string message, params object[] args) : this(true, inner, message, args) {} public override string Message { get { if (!_useFormat) return _formatStr; try { return string.Format(_formatStr, _arguments); } catch (Exception ex) { var sb = new StringBuilder(); sb.Append("Error formatting exception: "); sb.Append(ex.Message); sb.Append("\nFormat string: "); sb.Append(_formatStr); if (_arguments != null &amp;&amp; _arguments.Length &gt; 0) { sb.Append("\nArguments: "); for (int i = 0; i &lt; _arguments.Length; i++) { if (i &gt; 0) sb.Append(", "); try { sb.Append(_arguments[i]); } catch (Exception ex2) { sb.AppendFormat("(Argument #{0} cannot be shown: {1})", i, ex2.Message); } } } return sb.ToString(); } } } #region Serialization private const string SerializationField = "FormatString"; protected FormattedException(SerializationInfo info, StreamingContext context) : base(info, context) { _formatStr = (string) info.GetValue(SerializationField, typeof (string)); // Leave other values at their default } public override void GetObjectData(SerializationInfo info, StreamingContext context) { base.GetObjectData(info, context); // To avoid any serialization issues with param objects, format message now info.AddValue(SerializationField, Message, typeof (string)); } #endregion } </code></pre>
 

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