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POExpression.Or, The parameter 'item' is not in scope
 

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    <p>I am trying to write a static function to Or two expressions, but recieve the following error:</p> <blockquote> <p>The parameter 'item' is not in scope.</p> <p>Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. </p> <p>Exception Details: System.InvalidOperationException: The parameter 'item' is not in scope.</p> </blockquote> <p>the method:</p> <pre><code>public static Expression&lt;Func&lt;T, bool&gt;&gt; OrExpressions(Expression&lt;Func&lt;T, bool&gt;&gt; left, Expression&lt;Func&lt;T, bool&gt;&gt; right) { // Define the parameter to use var param = Expression.Parameter(typeof(T), "item"); var filterExpression = Expression.Lambda&lt;Func&lt;T, bool&gt;&gt; (Expression.Or( left.Body, right.Body ), param); // Build the expression and return it return (filterExpression); } </code></pre> <p><strong>edit</strong>: adding more info</p> <p>The expressions being or'd are coming from the method below, which execute just fine. if there is a better way to or the results I am all ears. Also, I do not know how many are being or'd in advance.</p> <pre><code>public static Expression&lt;Func&lt;T, bool&gt;&gt; FilterExpression(string filterBy, object Value, FilterBinaryExpression binaryExpression) { // Define the parameter to use var param = Expression.Parameter(typeof(T), "item"); // Filter expression on the value switch (binaryExpression) { case FilterBinaryExpression.Equal: { // Build an expression for "Is the parameter equal to the value" by employing reflection var filterExpression = Expression.Lambda&lt;Func&lt;T, bool&gt;&gt; (Expression.Equal( Expression.Convert(Expression.Property(param, filterBy), typeof(TVal)), Expression.Constant(Value) ), param); // Build the expression and return it return (filterExpression); } </code></pre> <p><strong>edit</strong>: adding even more info</p> <p>Alternatively, is there a better way to do an or? Currently the .Where(constraint) works just fine where constraint is of type Expression>. How can i do where(constraint1 or constraint2) (to the constraint n'th)</p> <p>Thanks in advance!</p>
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