public MyParameter AddWhereParameter(String columnName, MyOperand op, SQLiteParameter param, object value)
{
MyParameter my_param = new MyParameter(columnName, param)
{
Operator = op, Value = value
};
_whereParameters.Add(my_param);
return(my_param);
}
public static ExpressionType ToExpressionType(this MyOperand operand)
{
switch (operand)
{
case MyOperand.Greater: return(ExpressionType.GreaterThan);
case MyOperand.Less: return(ExpressionType.LessThan);
case MyOperand.Equal: return(ExpressionType.Equal);
default: throw new NotSupportedException();
}
}
public Predicate <T> GetFilterPredicate <T, R>(Expression <Func <T, R> > selector, MyOperand operand, R value)
{
var getExpressionBody = selector.Body as MemberExpression;
var parameter = Expression.Parameter(typeof(T), "u");
var left = Expression.Property(parameter, typeof(T).GetProperty(getExpressionBody.Member.Name));
var right = Expression.Constant(value);
var binaryExpression = Expression.MakeBinary(operand.ToExpressionType(), left, right);
return(Expression.Lambda <Predicate <T> >(binaryExpression, parameter).Compile());
}
