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    <p><strong>No</strong>, that is not good practice. You want to apply extension methods at the <strong>lowest possible point</strong>. I believe there a time and a place for (almost) everything, but extension methods <em>System.Object</em> would almost never be appropriate. You should be able to apply extension methods such as this much further down the inheritance stack. Otherwise it will clutter your intellisense and probably end up being used/depended-upon incorrectly by other developers.</p> <p>However, extension methods for data objects for dealing with Null values is a <strong>very good use</strong> of extension methods. Consider putting them right on you <em>OleDbDataReader</em>. I have a generic extension method called ValueOrDefault that . . . well, I'll just show it to you:</p> <pre><code>&lt;Extension()&gt; _ Public Function ValueOrDefault(Of T)(ByVal r As DataRow, ByVal fieldName As String) As T If r.IsNull(fieldName) Then If GetType(T) Is GetType(String) Then Return CType(CType("", Object), T) Else Return Nothing End If Else Return CType(r.Item(fieldName), T) End If End Function </code></pre> <p>That's VB, but you get the picture. This sucker saves me a ton of time and really makes for clean code when reading out of a datarow. <strong>You are on the right track</strong>, but your sense of spell is correct: you have the extension methods too high.</p> <p>Putting the extension methods into a separate namespace is better than nothing (this is a perfectly valid use of namespaces; Linq uses this), but you shouldn't have to. To make these methods apply to various db objects, apply the extension methods to <em>IDataRecord</em>.</p>
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    1. POGood practice to create extension methods that apply to System.Object?
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    1. USPatrick Karcher
    1. USPatrick Karcher
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    1. POGood practice to create extension methods that apply to System.Object?
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    1. COI found all answers helpful, but this one was the most helpful as it not only pointed out problems but also multiple solutions :) Thanks a lot!
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      1. USChristian
    2. CO@Patrick Karcher - I think your answer is pretty good (I voted it up), but missing one key element. You state strong feelings that it is wrong, but you do not spell out *why* it is wrong. Cluttering intellisense is true but not strong enough to match the strength of your feelings. "Used or depended on incorrectly" is vague, and you don't establish how having the method on Object would cause such a mistake. So ... is this just dogma on your part, or do you really have strong reasons for the way you feel?
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      1. USCharlie Flowers
 

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