private static IQueryable <T> SearchData <T>(DataTableAjaxModel model, IQueryable <T> dataSource)
{
if (!string.IsNullOrEmpty(model.Search?.Value))
{
var value = model.Search.Value;
var type = typeof(T);
var properties = type.GetProperties();
BinaryExpression body = null;
var p = Expression.Parameter(type);
foreach (var prop in properties)
{
BinaryExpression expression;
if (prop.PropertyType == typeof(int))
{
int.TryParse(value, out var val);
expression = GetBinaryExpression(p, prop, val);
}
else if (prop.PropertyType == typeof(string))
{
expression = GetBinaryExpression(p, prop, value);
}
else
{
continue;
}
if (prop == properties.First())
{
body = expression;
continue;
}
body = Expression.OrElse(body ?? throw new InvalidOperationException(), expression);
}
var lambda = Expression.Lambda(body ?? throw new InvalidOperationException(), new[] { p });
var whereCallExpression = Expression.Call(
typeof(Queryable),
"Where",
new[] { dataSource.ElementType },
dataSource.Expression,
Expression.Quote(lambda));
dataSource = dataSource.Provider.CreateQuery <T>(whereCallExpression);
}
return(dataSource);
}
/// <summary>
///
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="model"></param>
/// <param name="dataSource"></param>
/// <param name="result"></param>
/// <param name="totalCount"></param>
/// <param name="filtered"></param>
/// <returns></returns>
public static void Search <T>(this DataTableAjaxModel model, IQueryable <T> dataSource, out IQueryable <T> result, out int totalCount, out int filtered)
{
if (dataSource == null)
{
throw new ArgumentNullException(nameof(dataSource));
}
totalCount = dataSource.Count();
var take = model.Length;
var skip = model.Start;
//search
dataSource = SearchData(model, dataSource);
filtered = dataSource.Count();
//sort
dataSource = SortData(model, dataSource);
//paging
result = dataSource.Skip(skip).Take(take == -1 ? filtered : take);
}
private static IQueryable <T> SortData <T>(DataTableAjaxModel model, IQueryable <T> dataSource)
{
var sortBy = string.Empty;
var sortDir = string.Empty;
if (model.Order != null)
{
sortBy = model.Columns[model.Order[0].Column].Data;
sortDir = model.Order[0].Dir?.ToLower() == "desc" ? "OrderByDescending" : "OrderBy";
var type = typeof(T);
var property = type.GetProperty(sortBy);
var parameter = Expression.Parameter(type, "p");
var propertyAccess = Expression.MakeMemberAccess(parameter, property ?? throw new InvalidOperationException());
var orderByExp = Expression.Lambda(propertyAccess, parameter);
var resultExp = Expression.Call(
typeof(Queryable), sortDir,
new[] { type, property.PropertyType },
dataSource.Expression, Expression.Quote(orderByExp));
dataSource = dataSource.Provider.CreateQuery <T>(resultExp);
}
return(dataSource);
}
