Expression.Equal Method (Expression, Expression)
Creates a BinaryExpression that represents an equality comparison.
Assembly: System.Core (in System.Core.dll)
The resulting BinaryExpression has the Method property set to the implementing method. The Type property is set to the type of the node. If the node is lifted, the IsLifted property is true. Otherwise, it is false. The IsLiftedToNull property is always false. The following information describes the implementing method, the node type, and whether a node is lifted.
The following rules determine the implementing method for the operation:
Node Type and Lifted versus Non-Lifted
If the implementing method is not null:
If left.Type and right.Type are assignable to the corresponding argument types of the implementing method, the node is not lifted. The type of the node is the return type of the implementing method.
If the following two conditions are satisfied, the node is lifted and the type of the node is Boolean:
left.Type and right.Type are both value types of which at least one is nullable and the corresponding non-nullable types are equal to the corresponding argument types of the implementing method.
The return type of the implementing method is Boolean.
If the implementing method is null:
The following code example shows how to create an expression that checks whether the values of its two arguments are equal.
// Add the following directive to your file: // using System.Linq.Expressions; // This expression compares the values of its two arguments. // Both arguments need to be of the same type. Expression equalExpr = Expression.Equal( Expression.Constant(42), Expression.Constant(45) ); // Print out the expression. outputBlock.Text += equalExpr.ToString() + "\n"; // The following statement first creates an expression tree, // then compiles it, and then executes it. outputBlock.Text += Expression.Lambda<Func<bool>>(equalExpr).Compile()() + "\n"; // This code example produces the following output: // // (42 == 45) // False
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