Remove sorting of a flexgrid

Remove sorting of a flexgrid

Posted by: m-merciersynelia-fr on 27 September 2017, 9:07 pm EST

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  m-merciersynelia-fr

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  Posted 27 September 2017, 9:07 pm EST

  Hello,

  I have a flexgrid, wich has the AllowSorting property true. Every column of the flexgrid also have the AllowSorting property true.

  When i click on a column header, the column is sorted. OK, it’s normal.

  In my flexgrid, the user is allowed to update values, so my problem is that when a column is sorted, and a value is updated, the flexgrid sorts itself instantanately.

  I would like to be able to remove sorting informations of the flexgrid. I tried to use _flex.AllowSorting = false in the keydown event of the flexgrid, but it doesn’t work. As soon as i leave the cell, the flexgrid sorts itself again.

  Do you have an idea to solve my problem ?

• 

  nilayvishwkarma

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  Posted 27 September 2017, 9:07 pm EST

  Hi,

  In bound mode sorting is done automatically after list changes. This is why when any update is performed sorting is done automatically. This is a .NET behavior. In order for us to have a behavior where sorting is done only on request and that too in bound mode. We would have to create a custom DataSource. Thus we have following requirements from our DataSource:

  1. List should be sortable for every items.
  2. List should not sort when list changes.

  Here is our custom DataSource:

  SortableBindingList

  [csharp]
  
  using System;
  
  using System.Collections.Generic;
  
  using System.ComponentModel;
  
  using System.Linq;

  public class SortableBindingList : BindingList
  
  {
  
  private bool isSortedValue;
  
  ListSortDirection sortDirectionValue;
  
  PropertyDescriptor sortPropertyValue;

  public SortableBindingList()
  {
  }
  
  public SortableBindingList(IList<T> list)
  {
      foreach (object o in list)
      {
          this.Add((T)o);
      }
  }
  
  protected override void ApplySortCore(PropertyDescriptor prop,
      ListSortDirection direction)
  {
      Type interfaceType = prop.PropertyType.GetInterface("IComparable");
  
      if (interfaceType == null && prop.PropertyType.IsValueType)
      {
          Type underlyingType = Nullable.GetUnderlyingType(prop.PropertyType);
          if (underlyingType != null)
          {
              interfaceType = underlyingType.GetInterface("IComparable");
          }
      }
  
      if (interfaceType != null)
      {
          sortPropertyValue = prop;
          sortDirectionValue = direction;
          IEnumerable<T> query = base.Items;
          if (direction == ListSortDirection.Ascending)
          {
              query = query.OrderBy(i => prop.GetValue(i));
          }
          else
          {
              query = query.OrderByDescending(i => prop.GetValue(i));
          }
  
          int newIndex = 0;
          foreach (object item in query)
          {
              this.Items[newIndex] = (T)item;
              newIndex++;
          }
  
          isSortedValue = true;
          this.OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
      }
      else
      {
          throw new NotSupportedException("Cannot sort by " + prop.Name +
              ". This" + prop.PropertyType.ToString() +
              " does not implement IComparable");
      }
  }
  
  protected override PropertyDescriptor SortPropertyCore
  {
      get { return sortPropertyValue; }
  }
  
  protected override ListSortDirection SortDirectionCore
  {
      get { return sortDirectionValue; }
  }
  
  protected override bool SupportsSortingCore
  {
      get { return true; }
  }
  
  protected override bool IsSortedCore
  {
      get { return isSortedValue; }
  }
  
  protected override void OnListChanged(ListChangedEventArgs e)
  {
      base.OnListChanged(e);
      // Do not sort the list
  }
  

  }[/csharp]

  Please find the attached sample with complete implementation.

  ~nilay

  2016/11/RemoveSortingOfAFlexgrid.zip

• 

  yonit.chavshosh

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  Posted 30 January 2019, 6:03 am EST

  Hi,
  
  I have the same problem
  
  but I bound datatable to the flexGrid
  
  So I can’t use the SortableBindingList
  
  Do you have please another idea for me?

  Thanks,
  
  Yonit