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Show Hourglass Pointer on lengthy operations

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GridView

This is a migrated thread and some comments may be shown as answers.

17 Answers, 1 is accepted

answered on 17 Sep 2010, 11:49 PM

Hi Erwin,

Yes, it's a good point about changing the cursor in two places, but I don't think it would be up to the grid internally to manage the cursor either.
Don't have access to a dev environment at the moment, but from memory, I think you're right in that it doesn't fire when changing the direction of the coloumn. Just the change of column to sort on fires the event (which in my opinion is incorrect behaviour).

But even if the event fired at all the correct times, I'm not sure if there would be another way around it. Be interested to see what you come up with. If I think of another way, I'll be sure to post it.
Richard

answered on 21 Sep 2010, 04:08 PM

Hello guys,

Using SortChanging and SortChanged events is the right way to change the cursor to hourglass. However, it is true that SortChanging event does not fire if only the sort direction is changed. This is an issue and we are going to address it in the next release. Until the issue is addressed, however, there is no workaround that will allow you to implement the desired scenarion.

Best wishes,
Martin Vasilev
the Telerik team

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Accepted

answered on 24 Sep 2010, 10:32 PM

Hello guys,

I would suggest a workaround for the time being, it's not very clean and nice but it does what it should do, and until the SortChanging event will be fixed you don't need to use that method anymore.

First, in the form, register for the SortChanged event, and for the ContextMenuOpening event:

radGridView1.SortChanged += radGridView1_SortChanged;

radGridView1.GridBehavior = new MyBehavior();

radGridView1.ContextMenuOpening += radGridView1_ContextMenuOpening;

Second, we will create a custom behavior that checks if the left mouse click is in the cell header element and if so, set the Cursor to waiting state:

public class MyBehavior : BaseGridBehavior

{

protected override bool OnMouseDownLeft(MouseEventArgs e)

{

var element = this.GridControl.ElementTree.GetElementAtPoint(e.Location) as GridHeaderCellElement;

if (element != null)

{

this.GridControl.Cursor = Cursors.WaitCursor;

}

return base.OnMouseDownLeft(e);

}

After this we will create the SortChanged event where we can set the cursor to the default state:

private void radGridView1_SortChanged(object sender, Telerik.WinControls.UI.GridViewCollectionChangedEventArgs e)

{

this.radGridView1.Cursor = Cursors.Default;

}

With this everything will work fine if the user click on the table header element, but there is still on thing which we have to take care of if we are slowing also the header context menu, because sort operations can also be accessed from there,

void radGridView1_ContextMenuOpening(object sender, ContextMenuOpeningEventArgs e)

{

if (e.ContextMenuProvider == null)

{

return;

}

foreach (var item in e.ContextMenu.Items)

{

if (item.Text.ToLower().Contains("sort") && ((RadMenuItem)item).ToggleState != ToggleState.On)

{

item.MouseUp += item_MouseUp;

}

void item_MouseUp(object sender, MouseEventArgs e)

{

this.radGridView1.Cursor = Cursors.WaitCursor;

}

Here we are checking if the ContextMenuProvider is not null, and after that going trough all of the items in the menu, and those of which contain the sort keyword and are not currently selected we will register them for the MouseUp event to be able to set the cursor to waiting state before performing the operation.

I hope this helps, please let me know if there is something I've missed here.

By the way there is still one problem, when grouping not even the SortChanged event is fired after sorting...., if it were to fire then the custom behavior would change like this:

public class MyBehavior : BaseGridBehavior

{

protected override bool OnMouseDownLeft(MouseEventArgs e)

{

var element = this.GridControl.ElementTree.GetElementAtPoint(e.Location) as GridHeaderCellElement;

if (element != null)

{

this.GridControl.Cursor = Cursors.WaitCursor;

}

else if (this.GridControl.EnableGrouping)

{

var groupFieldElement = this.GridControl.ElementTree.GetElementAtPoint(e.Location) as GroupFieldElement;

if (groupFieldElement != null)

{

this.GridControl.Cursor = Cursors.WaitCursor;

}

return base.OnMouseDownLeft(e);

}

BUT, because that event doesn't fire either you will just have always a waiting cursor, so for the time being the previous version should be used...

Best regards,
Emanuel Varga

answered on 21 May 2013, 01:18 PM

Hi Wayne,

We introduced some performance improvements for the sorting operation in our latest release. The new implementation uses hybrid internal data structure that holds the sorted rows of RadGridView. The new implementation uses the quick sort algorithm when the Rows collection contains up to 10000 rows. When the Rows collection contains more than that the sorting operation uses a red-black binary tree to perform the operation.

However, this optimization might cause issue when there is repetitive data in the grid and in this situation the new algorithm works slower, so you will have to switch back to the old one. To do that we added new property to control this behavior. However, the new API will be available with next our release.

Currently, as a workaround you can change the sorting behavior using this code snippet based on reflection:

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

private void Form1_Load(object sender, EventArgs e)

{

IList<Book> bookList = new List<Book>();

for (int i = 0; i < 10000; i++)

{

bookList.Add(new Book { Price = new Random(i).NextDouble() * 100, HardCover = i % 2 == 0 ? "Y" : "N" });

}

grdBooks.DataSource = bookList;

grdBooks.SortChanging += new Telerik.WinControls.UI.GridViewCollectionChangingEventHandler(grdBooks_SortChanging);

}

bool initIndex = false;

void grdBooks_SortChanging(object sender, Telerik.WinControls.UI.GridViewCollectionChangingEventArgs e)

{

if (!initIndex)

{

AvlIndex<GridViewRowInfo> index = new AvlIndex<GridViewRowInfo>(grdBooks.MasterTemplate.DataView);

FieldInfo fieldInfo = typeof(RadDataView<GridViewRowInfo>).GetField("indexer", BindingFlags.GetField | BindingFlags.Instance | BindingFlags.NonPublic);

if (fieldInfo != null)

{

fieldInfo.SetValue(grdBooks.MasterTemplate.DataView, index);

}

fieldInfo = typeof(RadDataView<GridViewRowInfo>).GetField("groupBuilder", BindingFlags.GetField | BindingFlags.Instance | BindingFlags.NonPublic);

if (fieldInfo != null)

{

fieldInfo.SetValue(grdBooks.MasterTemplate.DataView, new GroupBuilder<GridViewRowInfo>(index));

}

initIndex = true;

}

If this does not help, please provide us with an example demonstrating the issue, so we can investigate it and help you resolve it. If you want, you can open a new support ticket where you can attach a whole project.

Looking forward to your reply.

Best wishes,
Martin Vasilev
the Telerik team

answered on 18 Oct 2013, 12:01 AM

Hi,

I've been following this to see why my code doesn't work. I'm only after the ability to change the cursor to an hourglass while I'm loading up my grid. I have a RadGridView on a windows form. I have a set of radio buttons containing 8 options for showing a list of products, of which there are about 5000 active at any one time. When the user selects one of the radio buttons and then clicks a "Search" button, I run the following code which does not change the cursor to an hourglass. Is the change of cursor only fired on a RadGridView event and if so, which one would I use in my case?

Thanks and best regards

Peter

With RadGridView2

.BeginUpdate()

.Cursor = Cursors.WaitCursor

.DataSource = Collection

.MasterTemplate.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill

.Dock = DockStyle.Fill

.MasterTemplate.AllowAddNewRow = False

.MasterTemplate.EnableSorting = True

Dim descriptor As New SortDescriptor()

descriptor.PropertyName = "Invoice_Description"

descriptor.Direction = ListSortDirection.Ascending

.MasterTemplate.SortDescriptors.Add(descriptor)

If .Rows.Count > 0 Then

.AllowEditRow = False

.AllowDeleteRow = False

.AllowAddNewRow = False

.Columns("EntityKey").IsVisible = False

.Columns("EntityDisplayName").IsVisible = False

.Columns("RowVersion").IsVisible = False

.Columns("ID").IsVisible = False

.Columns("CreationTime").IsVisible = False

.Columns("CreationUser").IsVisible = False

.Columns("LastWriteTime").IsVisible = False

.Columns("LastWriteUser").IsVisible = False

.Columns("Exclusive_CustomerID").IsVisible = False

.Columns("Exclusive_Customer").IsVisible = False

.Columns("BrandID").IsVisible = False

.Columns("UOM_UnitID").IsVisible = False

.Columns("UOM_ItemID").IsVisible = False

.Columns("Unit_Barcode").IsVisible = False

.Columns("Item_Barcode").IsVisible = False

.Columns("Unit_Weight").IsVisible = False

.Columns("Item_Weight").IsVisible = False

.Columns("Product_GroupID").IsVisible = False

.Columns("Unit_Actual_Cost").IsVisible = False

.Columns("Pallet_Quantity").IsVisible = False

.Columns("Pallet_Weight").IsVisible = False

.Columns("GST_Percentage").IsVisible = False

.Columns("Pallet_Layer_Quantity").IsVisible = False

.Columns("Supplier_Discount_Type_1").IsVisible = False

.Columns("Supplier_Discount_type_2").IsVisible = False

.Columns("Supplier_Discount_Amount_1").IsVisible = False

.Columns("Supplier_Discount_Amount_2").IsVisible = False

.Columns("Unit_Average_Cost").IsVisible = False

.Columns("Appropriation_Code").IsVisible = False

.Columns("Appropriation_CodeID").IsVisible = False

.Columns("Include_In_StockTake").IsVisible = False

.Columns("Is_Stocked_Product").IsVisible = False

.Columns("Is_BuyIn_Product").IsVisible = False

.Columns("Is_Specialty_Product").IsVisible = False

.Columns("Is_Quantity_Buy").IsVisible = False

.Columns("Is_Seasonal_Product").IsVisible = False

.Columns("Is_Halal_Product").IsVisible = False

.Columns("Is_Gluten_Free_Product").IsVisible = False

.Columns("Is_Vegetarian_Product").IsVisible = False

.Columns("Classification").IsVisible = False

.Columns("Sub_Classification").IsVisible = False

.Columns("ClassificationID").IsVisible = False

.Columns("Sub_ClassificationID").IsVisible = False

.Columns("School_Canteen_Colour").IsVisible = False

.Columns("Alternate_Code").IsVisible = False

.Columns("Alternate_Description").IsVisible = False

.Columns("Is_Discount_Allowed").IsVisible = False

.Columns("Freight_Category").IsVisible = False

.Columns("Freight_Cost").IsVisible = False

.Columns("Description_Brand_Size").IsVisible = False

.Columns("System_ComponentModel_IDataErrorInfo_Error").IsVisible = False

.Columns("CodeFluent_Runtime_Utilities_IKeyable_System_Int32__Key").IsVisible = False

.Columns("EntityState").IsVisible = False

For Each column As GridViewDataColumn In .Columns

column.BestFit()

column.ReadOnly = True

Next

RadGridView2.EndUpdate()

.Visible = True

Else

MsgBox("There are no Products matching your search criteria")

End If

RadGridView2.Cursor = Cursors.Default

End With

'Catch ex As Exception

' MsgBox("What's going on?")

'End Try

RadGridView2.Cursor = Cursors.Default

answered on 22 Oct 2013, 02:15 PM

Hello Peter,

Thank you for writing.

If you set the cursor of the grid and immediately start a heavy operation the grid has no time to process the Cursor request as the UI thread becomes busy. There are two solutions in this case:

Set the cursor and create a timer with some interval. In the timer's tick event start the heavy operations. This will give enough time for the grid to update its cursor.
Use the Cursor property of the Form. This will set the form's cursor while the grid processes the data:

void btn_Click(object sender, EventArgs e)

{

    this.Cursor = Cursors.WaitCursor;

    List<string> list = new List<string>();

    for (int i = 0; i < 100000; i++)

    {

        list.Add("STR");

    }

    this.grid.DataSource = list;

    this.Cursor = Cursors.Default;

}

I hope this will be suitable for your case. Let me know if there is anything else I can help you with.

Regards,
George
Telerik

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answered on 03 Nov 2013, 08:42 PM

Hi Martin,

I notice in your reply that the Q3 release might now have the option to change the sorting style by column to the old sort method?

I have 7 columns of which 6 sort great. One is a string column with a selection of string values which can repeat a lot and the sorting on this column takes upwards of 10 seconds with up to 8000 values. Is there now a way to change the sorting behaviour on just this column? I couldn't figure out an elegant way to do it, I was trying to create a numeric column based on the strings, have it hidden and then do a sort on that, but it caused issues with the normal sorting on other columns.

answered on 06 Nov 2013, 01:59 PM

Hello Kurt,

Thank you for contacting us.

The following code will change the Threshold which defines what algorithm to be used when sorting:

RadDataView<GridViewRowInfo> dataView =this.grid.GridViewElement.Template.ListSource.CollectionView as RadDataView<GridViewRowInfo>;

FieldInfo indexerField =typeof(RadDataView<GridViewRowInfo>).GetField("indexer", BindingFlags.NonPublic | BindingFlags.Instance);

HybridIndex<GridViewRowInfo> indexer = indexerField.GetValue(dataView) as HybridIndex<GridViewRowInfo>;

indexer.Threshold = 500;

With Threshold of 500 if the count of the data items is more than 500 the sorting operation will be performed with a BinaryTree.

I hope this helps.

Regards,
George
Telerik