public static IPagedList <T> GetPaged <T>(this QueryFluent <T> query, GridRequest request)
where T : EntityBase
{
return(query.Where(request.GetFilters <T>())
.OrderBy(request.GetSortExpression())
.Paged(request.Page, request.PageSize));
}
// Where
public static QueryFluent <TEntity> Where <TEntity>(this QueryFluent <TEntity> _this, Expression <Func <TEntity, bool> > predicate)
{
var body = predicate.Body;
switch (body)
{
case BinaryExpression binary:
var left = binary.Left as MemberExpression ?? throw new ArgumentException("Lhs must be PropertyAccess", nameof(predicate));
// Usually MethodCallExpression is passed.
// Sometimes UnaryExpression is passed even though the same syntax.
MethodCallExpression right;
switch (binary.Right)
{
case MethodCallExpression methodExp:
right = methodExp;
break;
case UnaryExpression unaryExp:
right = unaryExp.Operand as MethodCallExpression ?? throw new ArgumentException("Rhs must be Lt.Arg<>()", nameof(predicate));
break;
default:
throw new ArgumentException("Rhs must be Lt.Arg<>()", nameof(predicate));
}
string parameterName;
if (right.Arguments.Count == 0)
{
parameterName = left.Member.Name;
}
else
{
var arg = right.Arguments[0] as ConstantExpression ?? throw new ArgumentException("Rhs must be Lt.Arg<>()", nameof(predicate));
parameterName = (string)arg.Value ?? throw new ArgumentException("Lt.Arg<>() argment must not null", nameof(predicate));
}
switch (binary.NodeType)
{
case ExpressionType.Equal:
return(_this.Where(new EqualOperator(new Property <TEntity>(left.Member.Name), new Parameter(parameterName))));
default:
throw new NotSupportedException($"not supported convert [{binary.NodeType}]");
}
default:
throw new NotSupportedException($"not supported [{body}]");
}
}
