Hi Joemelle,
Thank you for contacting us.
You can implement a custom solution which will fit your needs. I have created a sample class which may get you started:
public class MyGridViewComboBoxColumn : GridViewComboBoxColumn
{
private IList dynamicDataSource;
private IList actualDataSource;
private int dataLoadStep = 100;
private RadDropDownListEditor comboBoxEditor;
private RadDropDownListElement editorElement;
private int savedScrollPosition;
public int DataLoadStep
{
get
{
return this.dataLoadStep;
}
set
{
if (value < 50)
{
throw new ArgumentException("The DataLoadStep can not be less than 50 so that a scrollbar can be visible after the initial load");
}
this.dataLoadStep = value;
}
}
public IList ActualDataSource
{
get
{
return this.actualDataSource;
}
set
{
this.actualDataSource = value;
this.DataSource = this.actualDataSource;
}
}
public IList DynamicDataSource
{
get
{
return this.dynamicDataSource;
}
set
{
if (this.actualDataSource == null)
{
throw new ArgumentException("Add a ActualDataSource first");
}
this.dynamicDataSource = value;
IList dataSource = (IList)this.DataSource;
for (int i = dataSource.Count; i < this.DataLoadStep; i++)
{
dataSource.Add(this.dynamicDataSource[i]);
}
}
}
public MyGridViewComboBoxColumn(int dataLoadStep)
:this()
{
this.DataLoadStep = dataLoadStep;
}
public MyGridViewComboBoxColumn()
:base()
{
}
public override void InitializeEditor(IInputEditor editor)
{
base.InitializeEditor(editor);
RadDropDownListEditor comboBoxEditor = editor as RadDropDownListEditor;
if (comboBoxEditor != null)
{
this.comboBoxEditor = comboBoxEditor;
RadDropDownListElement element = (RadDropDownListElement)comboBoxEditor.EditorElement;
if (element != null)
{
this.editorElement = element;
element.ListElement.VScrollBar.ValueChanged -= VScrollBar_ValueChanged;
element.ListElement.VScrollBar.ValueChanged += VScrollBar_ValueChanged;
}
}
}
private void VScrollBar_ValueChanged(object sender, EventArgs e)
{
RadScrollBarElement scroll = (RadScrollBarElement)sender;
if (scroll.Value + scroll.LargeChange >= scroll.Maximum - 400)
{
this.savedScrollPosition = scroll.Value;
this.LoadDataSource();
}
}
private void LoadDataSource()
{
IList currentDataSource = (IList)this.DataSource;
int maxCount = currentDataSource.Count + this.dataLoadStep;
if (maxCount < this.DynamicDataSource.Count)
{
for (int i = currentDataSource.Count; i < maxCount; i++)
{
object source = this.dynamicDataSource[i];
this.actualDataSource.Add(source);
}
this.comboBoxEditor.EndEdit();
this.InitializeEditor(this.comboBoxEditor);
this.editorElement.ShowPopup();
this.editorElement.ListElement.VScrollBar.Value = this.savedScrollPosition;
}
}
}
You can use it as follows:
My BindingClass has a single Property - "Name" and the bindlingCollection is a List<BindingClass>.
I hope this helps.
Regards,
George
Telerik
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