private FilterViewModel CreateFilterViewModel(string propertyName, string startValue, string endValue = "", Axiom.Common.Enumerations.FilterCondition condition = Axiom.Common.Enumerations.FilterCondition.Equals)
{
FilterViewModel filter = new FilterViewModel();
filter.PropertyName = propertyName;
filter.StartValue = startValue;
if (!string.IsNullOrEmpty(endValue))
filter.EndValue = endValue;
filter.WhereCondition = Axiom.Common.Enumerations.PredicateCondition.And;
filter.FilterCondition = condition;
return filter;
}
internal static void GetFilterExpression(FilterViewModel filter, Type type, ParameterExpression p, ref Expression predicateBody)
{
Expression exp = null, exp2 = null, left = null, right = null;
var pr = type.GetProperty(filter.PropertyName);
if (pr == null) return;
var prType = pr.PropertyType;
left = Expression.Property(p, pr);
if (prType == typeof(string))
left = Expression.Call(left, prType.GetMethod("ToLower", System.Type.EmptyTypes));
right = Expression.Constant(GetExpressionValue(filter.StartValue, prType), prType);
switch (filter.FilterCondition)
{
case FilterCondition.StartsWith:
exp = Expression.Call(left, Ax.GetFilterMethodName(FilterCondition.StartsWith), null, right);
break;
case FilterCondition.EndsWith:
exp = Expression.Call(left, Ax.GetFilterMethodName(FilterCondition.EndsWith), null, right);
break;
case FilterCondition.Contains:
exp = Expression.Call(left, Ax.GetFilterMethodName(FilterCondition.Contains), null, right);
break;
case FilterCondition.Equals:
exp = Expression.Equal(left, right);
break;
case FilterCondition.NotEqual:
exp = Expression.NotEqual(left, right);
break;
case FilterCondition.Greater:
exp = Expression.GreaterThan(left, right);
break;
case FilterCondition.Less:
exp = Expression.LessThan(left, right);
break;
case FilterCondition.Between:
exp = Expression.GreaterThan(left, right);
exp2 = Expression.LessThan(left, Expression.Constant(GetExpressionValue(filter.EndValue, prType), prType));
break;
default:
exp = Expression.Equal(left, right);
break;
}
if (predicateBody == null)
predicateBody = exp2 == null ? exp : Expression.And(exp, exp2);
else
{
if (filter.WhereCondition == PredicateCondition.Or)
{
predicateBody = exp2 == null ?
Expression.Or(predicateBody, exp) :
Expression.Or(predicateBody, Expression.And(exp, exp2));
}
else
{
predicateBody = exp2 == null ?
Expression.And(predicateBody, exp) :
Expression.And(predicateBody, Expression.And(exp, exp2));
}
}
}
