public Expression BuildExpression(Type type, Operator ruleOperator, object value, ParameterExpression parameterExpression)
{
ExpressionType expressionType = new ExpressionType();
var leftOperand = parameterExpression;
var rightOperand = Expression.Constant(Convert.ChangeType(value, type));
var expressionTypeValue = (ExpressionType)expressionType.GetType().GetField(Enum.GetName(typeof(Operator), ruleOperator)).GetValue(ruleOperator);
return(CastBuildExpression(expressionTypeValue, value, leftOperand, rightOperand));
}
public Expression BuildExpression <T>(string propertyName, Operator ruleOperator, object value, ParameterExpression parameterExpression)
{
ExpressionType expressionType = new ExpressionType();
var leftOperand = MemberExpression.Property(parameterExpression, propertyName);
var rightOperand = Expression.Constant(Convert.ChangeType(value, value.GetType()));
FieldInfo fieldInfo = expressionType.GetType().GetField(Enum.GetName(typeof(Operator), ruleOperator));
var expressionTypeValue = (ExpressionType)fieldInfo.GetValue(ruleOperator);
return(CastBuildExpression(expressionTypeValue, value, leftOperand, rightOperand));
}
public Expression BuildSubExpression(Operator ruleOperator,
Expression leftExpression,
Expression rightExpression)
{
ExpressionType expressionType = new ExpressionType();
FieldInfo fieldInfo = expressionType.GetType().GetField(Enum.GetName(typeof(Operator), ruleOperator));
var expressionTypeValue = (ExpressionType)fieldInfo.GetValue(ruleOperator);
if (ruleOperator == Operator.Not)
{
return(Expression.Not(leftExpression));
}
if (ruleOperator == Operator.IsTrue)
{
return(Expression.IsTrue(leftExpression));
}
return(Expression.MakeBinary(expressionTypeValue, leftExpression, rightExpression));
}
