public static IQueryable <TDb> OrderBy <TDb>(this IQueryable <TDb> source, OrderModel model)
{
var x = Expression.Parameter(source.ElementType, "x");
System.Linq.Expressions.LambdaExpression selector = null;
if ((model?.ByDistance ?? false))
{
var arr =
source.ToArray();
var parseMethod = typeof(double).GetMethod("Parse", new[] { typeof(string) });
var dbParameterXstr = Expression.PropertyOrField(x, "Latitude");
var dbParameterX =
Expression.Call(parseMethod, dbParameterXstr);
var dbParameterYstr = Expression.PropertyOrField(x, "Longitude");
var dbParameterY =
Expression.Call(parseMethod, dbParameterYstr);
var xParameterLocal = Expression.Constant(model.X);
var yParameterLocal = Expression.Constant(model.Y);
var xParameter = Expression.Subtract(dbParameterX, xParameterLocal);
var yParameter = Expression.Subtract(dbParameterY, yParameterLocal);
var xSquared = Expression.Multiply(xParameter, xParameter);
var ySquared = Expression.Multiply(yParameter, yParameter);
var sum = Expression.Add(xSquared, ySquared);
var sqrtMethod = typeof(Math).GetMethod("Sqrt", new[] { typeof(double) });
var distance = Expression.Call(sqrtMethod, sum);
selector = Expression.Lambda(
distance,
x);
}
else
{
selector = Expression.Lambda(Expression.PropertyOrField(x, model.PropertyName), x);
}
return
(source.Provider.CreateQuery <TDb>(
Expression.Call(typeof(Queryable), model.IsDes ? "OrderByDescending" : "OrderBy",
new Type[] { source.ElementType, selector.Body.Type },
source.Expression, selector
)));
}
public static IQueryable <TDb> OrderBy3 <TDb>(this IQueryable <TDb> source, OrderModel model)
{
var x = Expression.Parameter(source.ElementType, "x");
System.Linq.Expressions.LambdaExpression selector = null;
if ((model?.ByDistance ?? false))
{
var parseMethod = typeof(double).GetMethod("Parse", new[] { typeof(string) });
var dbParameterXstr = Expression.PropertyOrField(x, "Latitude");
var dbParameterX =
Expression.Call(parseMethod, dbParameterXstr);
var dbParameterYstr = Expression.PropertyOrField(x, "Longitude");
var dbParameterY =
Expression.Call(parseMethod, dbParameterYstr);
var xParameterLocal = Expression.Constant(model.X);
var yParameterLocal = Expression.Constant(model.Y);
var sqrtMethod = typeof(Math).GetMethod("Sqrt", new[] { typeof(double) });
var cosMethod = typeof(Math).GetMethod("Cos", new[] { typeof(double) });
var asinMethod = typeof(Math).GetMethod("Asin", new[] { typeof(double) });
var pParameter = Expression.Constant(0.017453292519943295);
var latSubst = Expression.Subtract(dbParameterX, xParameterLocal);
var latSubstP = Expression.Multiply(latSubst, pParameter);
var cosLatSubstP = Expression.Call(cosMethod, latSubstP);
var cosLatSubstPdiv2 = Expression.Divide(cosLatSubstP, Expression.Constant(2.0));
var locLatP = Expression.Multiply(xParameterLocal, pParameter);
var cosLocLatP = Expression.Call(cosMethod, locLatP);
var dbLatP = Expression.Multiply(dbParameterX, pParameter);
var cosDbLatP = Expression.Call(cosMethod, dbLatP);
var longSubst = Expression.Subtract(dbParameterY, yParameterLocal);
var longSubstP = Expression.Multiply(longSubst, pParameter);
var cosLongSubstP = Expression.Call(cosMethod, longSubstP);
var oneSubstCosLongSubstP = Expression.Subtract(Expression.Constant(1.0), cosLongSubstP);
var oneSubstCosLongSubstPdiv2 = Expression.Divide(oneSubstCosLongSubstP, Expression.Constant(2.0));
var mult12 =
Expression.Multiply(cosLocLatP, cosDbLatP);
var mult123 = Expression.Multiply(mult12, oneSubstCosLongSubstPdiv2);
var res =
Expression.Subtract(Expression.Constant(0.5), cosLatSubstPdiv2);
var res2 =
Expression.Add(res, mult123);
var sqrtRes = Expression.Call(sqrtMethod, res2);
var asinSqrtRes = Expression.Call(asinMethod, sqrtRes);
var distance = Expression.Multiply(Expression.Constant(12742.0), asinSqrtRes);
selector = Expression.Lambda(
distance,
x);
}
else
{
selector = Expression.Lambda(Expression.PropertyOrField(x, model.PropertyName), x);
}
return
(source.Provider.CreateQuery <TDb>(
Expression.Call(typeof(Queryable), model.IsDes ? "OrderByDescending" : "OrderBy",
new Type[] { source.ElementType, selector.Body.Type },
source.Expression, selector
)));
}
public static IQueryable <TDb> OrderBy2 <TDb>(this IQueryable <TDb> source, OrderModel model)
{
var x = Expression.Parameter(source.ElementType, "x");
System.Linq.Expressions.LambdaExpression selector = null;
if ((model?.ByDistance ?? false))
{
var parseMethod = typeof(double).GetMethod("Parse", new[] { typeof(string) });
var dbParameterXstr = Expression.PropertyOrField(x, "Latitude");
var dbParameterX =
Expression.Call(parseMethod, dbParameterXstr);
var dbParameterYstr = Expression.PropertyOrField(x, "Longitude");
var dbParameterY =
Expression.Call(parseMethod, dbParameterYstr);
var xParameterLocal = Expression.Constant(model.X);
var yParameterLocal = Expression.Constant(model.Y);
var cosMethod = typeof(Math).GetMethod("Cos", new[] { typeof(double) });
var sinMethod = typeof(Math).GetMethod("Sin", new[] { typeof(double) });
var acosMethod = typeof(Math).GetMethod("Acos", new[] { typeof(double) });
Expression Sin(Expression target)
{
return(Expression.Call(sinMethod, target));
}
Expression Cos(Expression target)
{
return(Expression.Call(cosMethod, target));
}
Expression Acos(Expression target)
{
return(Expression.Call(acosMethod, target));
}
var baseRadEx = Expression.Multiply(Expression.Constant(Math.PI),
Expression.Divide(xParameterLocal, Expression.Constant(180.0)));
var targetRadEx = Expression.Multiply(Expression.Constant(Math.PI),
Expression.Divide(dbParameterX, Expression.Constant(180.0)));
var thetaEx = Expression.Subtract(yParameterLocal, dbParameterY);
var thetaRadEx = Expression.Multiply(Expression.Constant(Math.PI),
Expression.Divide(thetaEx, Expression.Constant(180.0)));
var distEx =
Add(Mult(Sin(baseRadEx), Sin(thetaRadEx)),
Mult(Cos(thetaRadEx), Mult(Cos(baseRadEx), Cos(targetRadEx))));
var dist2Ex =
Acos(distEx);
var dist3Ex =
Div(Mult(dist2Ex, Expression.Constant(180.0)), Expression.Constant(Math.PI));
var distance =
Mult(dist3Ex, Expression.Constant(111.18957696));
selector = Expression.Lambda(
distance,
x);
}
else
{
selector = Expression.Lambda(Expression.PropertyOrField(x, model.PropertyName), x);
}
return
(source.Provider.CreateQuery <TDb>(
Expression.Call(typeof(Queryable), model.IsDes ? "OrderByDescending" : "OrderBy",
new Type[] { source.ElementType, selector.Body.Type },
source.Expression, selector
)));
}