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copied!<p>Ultimately it depends on the particular implementation of <code>System.Data.IDataReader</code> you are referring to, but let's assume you mean <code>System.Data.SqlClient.SqlDataReader</code>.</p> <p>In this case, <code>reader[i]</code> and <code>reader.GetValue(i)</code> do <em>exactly</em> the same thing. In fact, <code>reader[i]</code> internally calls <code>reader.GetValue(i)</code>. (You can see this by disassembling the code using a tool like <a href="http://wiki.sharpdevelop.net/ILSpy.ashx">ILSpy</a>.). Both these members return the value in the i-th column of the current row and will return successfully regardless of the type of the value (the return type is <code>object</code>). The documentation for both of these members is a little misleading and could be worded in a better way. You can use either of these members wherever you like, just pick the one which you feel reads better.</p> <p>Whereas <code>reader.GetString(i)</code> is specifically designed to return the value contained in the i-th column of the current row as a <code>string</code>. If the value in that column is not a <code>string</code>, an <code>InvalidCastException</code> will be thrown. Use this method when you are sure that the value is a <code>string</code> and <code>string</code> is the type that you want to work with. This will make your code more concise since you won't have to perform a cast.</p> <p>In your specific case, the value in the i-th column of the current row must be of type <code>string</code>, which is why the return value of all three members is identical.</p> <p>If written correctly, other implementations of <code>System.Data.IDataReader</code> should behave in the same way.</p>

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