Difficulty binding checkbox using MVVM Patten
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04-01-2011 08:01 AM
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Hello all,
I'm trying to get my head around the MVVM pattern; the journey has presented some interesting stumbling blocks. What I have here is an effort to convert existing code architecture to leverage MVVM.
Basic components: SearchResultWindow.xaml, SearchResultWindow.xaml.cs, SearchViewModel.
General Overview:
I have a DataTemplate defined as a resource in my SearchResultWindow.xaml file. In the codebehind for this page, I have a method that builds a items in a treeview dynamically based on data returned from a WCF. Within each treeview item, we dynamically create a DataGrid and add it to the treeview item. When one of these treeview nodes is expanded, the DataGrid contained therein will be populated via a method in the SearchViewModel that calls a WCF Service. The datagrid???s columns are built dynamically because it is unknown how many columns are needed based on the data coming back from the WCF Service. Additionally, we use the DataTemplate resource from our xaml file to dynamically create a DataGridTemplateColumn containing a checkbox and adding this column to the datagrid.
Here is the problem: The DataGrid binds to SearchViewModel.FeatureAttributeDataGridRows which is a collection of dictionary items that have been converted using IValueConverter while binding the dictionary object to the column. Although this works well for the DataGridTextColumns I cannot seem to find a way to achieve the CheckBox binding for the CheckBoxes contained in the DataTemplateColumn. These CheckBoxes must be bound to the Feature.IsSelected property, which is not a member of the FeatureAttributeDataGridRows collection. The ???Feature??? class is an inner class contained in the SearchViewModel. A collection of Features exist as a property of the FeatureClass class (another inner class in SearchViewModel), as you will see in the GetFeatureClassFeatures method. I have not included the code that makes up these inner classes. Following an MVVM pattern, how should I bind the IsSelected property of the Feature class object to the DataGridTemplateColumn AND bind the other columns of the datagrid to the SearchViewModel.FeatureAttributeDataGridRows? Any help getting these CheckBoxes bound would be appreciated. Following are some code snippets:
Beginning with the xaml, I have a DataGridTemplateColumn setup with the intention of binding the checkboxes contained in this column to a property in the SearchViewModel.
*Codebehind for SearchResultWindow:
In the codebehind I have a method that creates and populates a treeview:
I???ve slimmed this down for the sake of brevity; the main component of interest here is DataGrid dgFeatureDetails
This DataGrid will get created several times in this loop, one for each top level node in the tree.
* SearchViewModel Snip
Any help here will certainly be appreciated! TIA
I'm trying to get my head around the MVVM pattern; the journey has presented some interesting stumbling blocks. What I have here is an effort to convert existing code architecture to leverage MVVM.
Basic components: SearchResultWindow.xaml, SearchResultWindow.xaml.cs, SearchViewModel.
General Overview:
I have a DataTemplate defined as a resource in my SearchResultWindow.xaml file. In the codebehind for this page, I have a method that builds a items in a treeview dynamically based on data returned from a WCF. Within each treeview item, we dynamically create a DataGrid and add it to the treeview item. When one of these treeview nodes is expanded, the DataGrid contained therein will be populated via a method in the SearchViewModel that calls a WCF Service. The datagrid???s columns are built dynamically because it is unknown how many columns are needed based on the data coming back from the WCF Service. Additionally, we use the DataTemplate resource from our xaml file to dynamically create a DataGridTemplateColumn containing a checkbox and adding this column to the datagrid.
Here is the problem: The DataGrid binds to SearchViewModel.FeatureAttributeDataGridRows which is a collection of dictionary items that have been converted using IValueConverter while binding the dictionary object to the column. Although this works well for the DataGridTextColumns I cannot seem to find a way to achieve the CheckBox binding for the CheckBoxes contained in the DataTemplateColumn. These CheckBoxes must be bound to the Feature.IsSelected property, which is not a member of the FeatureAttributeDataGridRows collection. The ???Feature??? class is an inner class contained in the SearchViewModel. A collection of Features exist as a property of the FeatureClass class (another inner class in SearchViewModel), as you will see in the GetFeatureClassFeatures method. I have not included the code that makes up these inner classes. Following an MVVM pattern, how should I bind the IsSelected property of the Feature class object to the DataGridTemplateColumn AND bind the other columns of the datagrid to the SearchViewModel.FeatureAttributeDataGridRows? Any help getting these CheckBoxes bound would be appreciated. Following are some code snippets:
Beginning with the xaml, I have a DataGridTemplateColumn setup with the intention of binding the checkboxes contained in this column to a property in the SearchViewModel.
*Codebehind for SearchResultWindow:
In the codebehind I have a method that creates and populates a treeview:
I???ve slimmed this down for the sake of brevity; the main component of interest here is DataGrid dgFeatureDetails
This DataGrid will get created several times in this loop, one for each top level node in the tree.
* SearchViewModel Snip
Any help here will certainly be appreciated! TIA
