public override DbExpression Visit(DbIsNullExpression expression)
{
DebugCheck.NotNull(expression);
var propertyExpression
= expression.Argument as DbPropertyExpression;
if (propertyExpression != null)
{
var parameter
= GetParameter((EdmProperty)propertyExpression.Property, originalValue: true);
if (parameter != null)
{
if (parameter.Item2)
{
// Current value, remove condition
return(null);
}
var parameterReferenceExpression
= new DbParameterReferenceExpression(parameter.Item1.TypeUsage, parameter.Item1.Name);
var equalityPredicate
= propertyExpression.Equal(parameterReferenceExpression);
var nullPredicate
= propertyExpression.IsNull().And(parameterReferenceExpression.IsNull());
return(equalityPredicate.Or(nullPredicate));
}
}
return(base.Visit(expression));
}
public override DbExpression Visit(DbIsNullExpression expression)
{
DbPropertyExpression left = expression.Argument as DbPropertyExpression;
if (left != null)
{
Tuple <FunctionParameter, bool> parameter = this.GetParameter((EdmProperty)left.Property, true);
if (parameter != null)
{
if (parameter.Item2)
{
return((DbExpression)null);
}
DbParameterReferenceExpression referenceExpression = new DbParameterReferenceExpression(parameter.Item1.TypeUsage, parameter.Item1.Name);
return((DbExpression)left.Equal((DbExpression)referenceExpression).Or((DbExpression)left.IsNull().And((DbExpression)referenceExpression.IsNull())));
}
}
return(base.Visit(expression));
}