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Grid scrolling to bottom row after a datasource refresh

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GridView

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

Fred asked on 13 Oct 2010, 03:39 PM

Hello,

I've got a problem with the GridView I cannot explain, when I reassign the datasources for a hierarchic grid after having selected a child, the grid will always scroll to the bottom on trying to select children after the datasource is reset. It seems like it's internal offset list has been corrupted or something like that. I've made the most simple test case, so hopefully someone can reproduce this problem and tell me what I'm doing wrong. I've seen examples just reassign the datasource so that should be no problem, but maybe I'm missing some step. I did see someone reference this behaviour in another post Errors clicking on childrows of heirarchical gridview on the forum (the case 2), but no proposed solution was given. So I'm kinda stuck and any help would be very much appreciated.

TestGridForm2.cs

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using Telerik.WinControls.UI;

using Telerik.WinControls.Enumerations;

namespace RadGridViewProblems

{

/*

* Demonstate a gridview problem when setting the datasource a second time (or more) when a child row is clicked

* the grid scrolls to the bottom, reason/workaround: unknown

*/

public partial class TestGridForm2 : RadForm

{

public TestGridForm2()

{

InitializeComponent();

this.Load += new EventHandler(FormLoaded);

}

private void FormLoaded(object sender, EventArgs e)

{

//testGridView.ReadOnly = true;

testGridView.AutoGenerateColumns = true;

childGridViewTemplate = new GridViewTemplate();

childGridViewTemplate.AutoGenerateColumns = true;

testGridView.MasterTemplate.ShowRowHeaderColumn = true;

childGridViewTemplate.ShowRowHeaderColumn = false;

testGridView.MasterTemplate.Templates.Add(childGridViewTemplate);

GridViewRelation relation = new GridViewRelation(testGridView.MasterTemplate);

relation.ChildTemplate = childGridViewTemplate;

relation.RelationName = "ParentChildren";

relation.ParentColumnNames.Add("id");

relation.ChildColumnNames.Add("parent_id");

testGridView.Relations.Add(relation);

LoadData();

}

private void LoadData()

{

/*childGridViewTemplate.DataSource = null;

testGridView.DataSource = null;*/

List<MyParentClass> myParentList = new List<MyParentClass>();

for(int i=1; i<=100; i++)

{

myParentList.Add(new MyParentClass() { id = i, name = i.ToString(), info = "blabla" });

}

List<MyChildClass> myChildList = new List<MyChildClass>();

Random random = new Random(1);

for(int i=1; i<=300; i++)

{

myChildList.Add(new MyChildClass() { parent_id = random.Next(1,100), id = i, name = i.ToString(), info = "blabla" });

}

childGridViewTemplate.DataSource = myChildList;

testGridView.DataSource = myParentList;

}

private void resetButton_Click(object sender, EventArgs e)

{

LoadData();

}

private GridViewTemplate childGridViewTemplate;

}

TestGridForm2.Designer.cs

namespace RadGridViewProblems

{

partial class TestGridForm2

{

/// <summary>

/// Required designer variable.

/// </summary>

private System.ComponentModel.IContainer components = null;

/// <summary>

/// Clean up any resources being used.

/// </summary>

/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>

protected override void Dispose(bool disposing)

{

if(disposing && (components != null))

{

components.Dispose();

}

base.Dispose(disposing);

}

#region Windows Form Designer generated code

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

private void InitializeComponent()

{

this.testGridView = new Telerik.WinControls.UI.RadGridView();

this.resetButton = new Telerik.WinControls.UI.RadButton();

((System.ComponentModel.ISupportInitialize)(this.testGridView)).BeginInit();

((System.ComponentModel.ISupportInitialize)(this.resetButton)).BeginInit();

((System.ComponentModel.ISupportInitialize)(this)).BeginInit();

this.SuspendLayout();

//

// testGridView

//

this.testGridView.Dock = System.Windows.Forms.DockStyle.Fill;

this.testGridView.Location = new System.Drawing.Point(0, 0);

this.testGridView.Name = "testGridView";

this.testGridView.Padding = new System.Windows.Forms.Padding(0, 0, 0, 1);

//

this.testGridView.RootElement.Padding = new System.Windows.Forms.Padding(0, 0, 0, 1);

this.testGridView.Size = new System.Drawing.Size(833, 444);

this.testGridView.TabIndex = 0;

this.testGridView.Text = "radGridView1";

//

// resetButton

//

this.resetButton.Location = new System.Drawing.Point(90, 460);

this.resetButton.Name = "resetButton";

this.resetButton.Size = new System.Drawing.Size(130, 24);

this.resetButton.TabIndex = 1;

this.resetButton.Text = "Reset datasources";

this.resetButton.Click += new System.EventHandler(this.resetButton_Click);

//

// TestGridForm2

//

this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);

this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;

this.ClientSize = new System.Drawing.Size(833, 494);

this.Controls.Add(this.resetButton);

this.Controls.Add(this.testGridView);

this.Name = "TestGridForm2";

this.Padding = new System.Windows.Forms.Padding(0, 0, 0, 50);

//

this.RootElement.ApplyShapeToControl = true;

this.Text = "Test Form";

((System.ComponentModel.ISupportInitialize)(this.testGridView)).EndInit();

((System.ComponentModel.ISupportInitialize)(this.resetButton)).EndInit();

((System.ComponentModel.ISupportInitialize)(this)).EndInit();

this.ResumeLayout(false);

}

#endregion

private Telerik.WinControls.UI.RadGridView testGridView;

private Telerik.WinControls.UI.RadButton resetButton;

}

Thanks
Frederik

11 Answers, 1 is accepted

answered on 15 Oct 2010, 11:31 AM

Hello,

I haven't tried yet with upgrading, the project leader has to give the go for that and he seems not to believe it's a problem with the version (I did mention there are reportedly *a lot* of bugfixes in that last version). I do think it a version problem but I haven't actually heard confirmation if this second problem with scrolling to the bottom can be reproduced, but I suspect it can't just like my other problem with the crash.

Emanuel>
I have tried switching those two lines, and strangely even though in the real application they *are* in parent, then child order to assign the datasources, the behaviour indeed becomes different in my test case, being it doesn't scroll to the bottom anymore when selecting a child. There is however a new problem, a random row is selected and the child view automatically expanded on that row (again *if* you selected a child first before refreshing). I have tried clearing the selection, since that seemed to be the determining factor for the problem to occur, and collapsing all rows as you suggested but that seems to have no effect.

In any case, I know I should probably just upgrade to the latest version and come back to you guys if I still have a problem then but could you tell me if you have actually been able to reproduce this scrolling to the bottom problem using my test case? I'm not sure if you did from your posts.

Anyway thanks a lot for the assistance, great first-line support.

Greetings
Frederik

ps. my version is RadControls_WinForms_2010_2_10_806_dev

answered on 15 Oct 2010, 01:07 PM

Hi,

great you guys can reproduce it, so I know I'm not alone, but not so great considering this will mean a workaround or waiting for next release.

Concerning a workaround, I have already tried when resetting datasource to clear the selection and collapse all children (but no effect):

ExpandAllChildren(false);

testGridView.ClearSelection();

testGridView.DataSource = myParentList;

childGridViewTemplate.DataSource = myChildList;

where ExpandAllChildren is:

private void ExpandAllChildren(Boolean expand)

{

foreach(GridViewDataRowInfo row in testGridView.Rows)

{

if(row is GridViewHierarchyRowInfo)

row.IsExpanded = expand;

}

If you *could* find a way around the problem that would be very much appreciated and thanks anyway for your attention to this problem.

Greetings
Frederik

Accepted

answered on 15 Oct 2010, 01:14 PM

Hello again, I have a solution, but you won't like it, because honestly it's kinnda stupid but it works, it's about removing the child template and relations and create them again on rebind...

Something like:

private void ClearAndCreateTemplateAndRelation()

{

if (testGridView.Templates.Count != 0)

{

testGridView.Templates.Clear();

if (testGridView.Relations.Count != 0)

{

testGridView.Relations.Clear();

}

childGridViewTemplate = new GridViewTemplate();

childGridViewTemplate.AutoGenerateColumns = true;

testGridView.MasterTemplate.ShowRowHeaderColumn = true;

childGridViewTemplate.ShowRowHeaderColumn = false;

childGridViewTemplate.SelectLastAddedRow = false;

testGridView.MasterTemplate.Templates.Add(childGridViewTemplate);

GridViewRelation relation = new GridViewRelation(testGridView.MasterTemplate);

relation.ChildTemplate = childGridViewTemplate;

childGridViewTemplate.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;

relation.RelationName = "ParentChildren";

relation.ParentColumnNames.Add("id");

relation.ChildColumnNames.Add("parent_id");

testGridView.Relations.Add(relation);

}

But maybe, if you don't have a really large number of records in the grid it will work as a TEMPORARY patch.

Please let me know how it goes.

Best Regards,
Emanuel Varga

Accepted