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kinetico
Joined: 31 Aug 2007
Posts: 7
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 Posted: Thu Sep 20, 2007 8:37 pm Post subject: virtual dropdown list as editor |
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Hi all,
I use virtual tree to display Parent Child data on the screen. However, the child object has a property that references another object. Example
Parent obejct - Group
Child object - Attribute
Child object property - Attribute.Unit
The Unit object has ID and Description.
I need to display data in the following format:
Group1
Attribute1 Unit1
Attribute2 Unit2
Attribute3 Unit3
** Unit1 is a value of the Unit.Description property
I also would like to use virtual dropdown list as an editor populating it with the distinct list of Units.
Please help!!!
TIA
Milena |
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Infralution
Joined: 28 Feb 2005
Posts: 5027
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| Posted: Fri Sep 21, 2007 12:10 am Post subject: |
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Create a new Editor (using the Virtual Tree designer) and set the editor control to be a VirtualDropDownList. Set the Column.Editor property to this Editor. In your code, following the InitializeComponent, set the DataSource of the editor control eg
| Code: | | testDropDownList.DataSource = unitList; |
Where unitList is a list of the possible Unit objects. Override the ToString method of the Unit class to return the Description of the Unit. Then (if you are using ObjectBinding) you can simply bind the Attribute.Unit property to the column.
The only other issue to resolve is that the .NET databinding design includes a mechanism to keep the selected items of databound controls (bound to the same datasource) on a form in sync via the BindingContext/CurrencyManager. To avoid all of the drop down controls changing selection in sync you need to disconnect them and give each control its own BindingContext. You do this by handling the CellEditor.IntializeControl event as follows:
| Code: | private void cellEditor2_InitializeControl(object sender, CellEditorInitializeEventArgs e)
{
if (e.NewControl)
{
e.Control.BindingContext = new BindingContext();
}
} |
We will be changing VirtualTree in the next release so that it gives each control its own binding context by default (so you won't have to do this)
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Infralution Support |
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kinetico
Joined: 31 Aug 2007
Posts: 7
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| Posted: Fri Sep 21, 2007 1:37 pm Post subject: |
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Thank you very much for your great advice. I did everything you said and it resolved some of the issues.
Here is what can't work out. The unit column is bound to Attribute.Unit property. However, when I load the form none of the data is displayed in the Unit column.
Do I need to handle it in GetCellData event handler by setting e.celldata.value = attribute.unit.tostring
Is there any other way?
Thank very much for your help
Milena Voronkin |
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Infralution
Joined: 28 Feb 2005
Posts: 5027
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| Posted: Fri Sep 21, 2007 10:03 pm Post subject: |
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If you have implemented Unit.ToString() to display the description then simply binding to the Attribute.Unit property should display the description.
You could add a GetCellData handler - to see if there is an issue with your object binding, but you should set e.celldata.value = attribute.unit. Otherwise you won't be able to select the Unit using your drop down list (because the bound object will be a string not a Unit object).
If you could put together a sample project that illustrates your problem and email a zipped copy to support@infralution.com we could probably sort the issue out for you.
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Infralution Support |
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Infralution
Joined: 28 Feb 2005
Posts: 5027
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| Posted: Mon Sep 24, 2007 2:06 am Post subject: |
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We have now released Version 3.5.6 of Virtual Tree. This version creates a separate binding context for each editor control by default. This eliminates the need to do this programmatically when using bound list controls as editors.
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Infralution Support |
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