I have a DataTable that has several DataColumns and DataRow. Now i would like to handle an event when cell of this DataRow is changed. How to do this in c#?
It looks as though the DataTable.ColumnChanged event will do what you want
http://msdn.microsoft.com/en-us/library/system.data.datatable.columnchanged.aspx
Related
Need to do some logic based on the current row selected. New to WPF before I would do something like this;
int i myDataGridView.CurrentCell.RowIndex
Now that is not available, what is best way to get selected row?
Use DataGrid.SelectedItem property. It gives the Selected Item on the DataGrid if SelectionMode is Single. Else DataGrid.SelectedItems gives the multiple selection if SelectionMode is Extended or Multiple
Try this:
SomeObject someObject = (SomeObject)myDataGridView.SelectedItem
i have a datagrid bound to a property. In this grid i have columns which consists of cells which are like hyperlink i mean when user clicks on the cell value based on these values another gird will get populated. i want to know how to get the cell value and pass it to some method so that other grid will get populated.
The best way to do this is in your viewmodel.
You should bind the SelectedItem of your datagrid to a new property in your ViewModel. In the set method of this new Property, call a new method to populate a new ObservableCollection/List/whatever...
Finally, bind your "other grid" ItemsSource to this new observable collection from your ViewModel.
Edit:
If you need to load one thing or another depending on the column you are going to use the code behind, take a look at this:
Silverlight DataGrid how to get cell value from a selected item?
I'm using wpf drag and drop databinding to datasets. I generate a new datatable row using the AddNew method of the BindingListCollectionView. I set values on the new row and call CommitNew on the BindingListCollectionView. I expect to see my assigned values in the bound controls but they are all blank. If I save the changes to the database the controls are then updated, but I want the user to see my assigned values before calling UpdateAll on the TableAdapterManager.
Background:
I've created a strongly typed dataset in a project separate from my wpf application. My wpf app references the dataset application. I added an object datasource in the wpf app pointing to the typed dataset. I dragged fields/controls from the datasources window to the wpf designer window. The generated xaml includes a Window.Resources section with a CollectionViewSource accurately bound to my dataset and datatable. This CollectionViewSource is the DataContext for the controls that I dragged to the design surface. All of the controls use TwoWay databinding.
When the window loads I grab a reference to the xaml's CollectionViewSource (using FindResource). I then grab a reference to the view property of the CollectionViewSource and cast it to a BindingListCollectionView. Now I use the AddNew method of the BindingListCollectionView to generate a new row (which AddNew returns as an object). I cast the object to a DataRowView and access it's Row property. I then cast the row to a strongly typed datatable row (generated by the DataSet designer). Now I assign values to some of the datatable row columns. I call CommitNew on the BindingListCollectionView. Finally I call MoveCurrentToFirst on the CollectionViewSource.
Problem:
Using a watch expression I can see the data is in the SourceCollection of both the CollectionView and the BindingListCollectionView. Can anyone explain why the bound controls do not show the data unless I save the changes to the database?
Code (generated XAML not shown):
Private WithEvents _cvsScanData As System.Windows.Data.CollectionViewSource
Private WithEvents _blcvScanData As System.Windows.Data.BindingListCollectionView
_cvsScanData = CType(Me.FindResource("Dt_tblScanDataViewSource"), System.Windows.Data.CollectionViewSource)
_blcvScanData = CType(_cvsScanData.View, BindingListCollectionView)
Dim newRow As LabDataSet.dt_tblScanDataRow = CType(CType(_blcvScanData.AddNew, System.Data.DataRowView).Row, LabDataSet.dt_tblScanDataRow)
newRow.SampleID = "testSampleID"
newRow.MachineID = "testMachineID"
_blcvScanData.CommitNew()
_cvsScanData.View.MoveCurrentToFirst()
The simple fix is to call the Refresh method of the BindingListCollectionView after calling CommitNew.
_blcvScanData.Refresh()
I stumbled across this answer to my own question via intellisense. If anyone can explain why refresh is necessary I'd appreciate it. I expected the INotifyPropertyChange interface to update the bound controls obviating the need to call refresh.
I have a datagrid in my View with it's ItemSource bound to a DataTable in my ViewModel. When I update the DataTable programmatically (adding a column through a command) the changes are not populated to the View. Also, if I invalidate the View, by switching to another tab and then switching back, the changes made are shown.
My ViewModel inherits from INotifyPropertyChanged, and I am raising the PropertyChanged event correctly since I use the same process for other bound properties in the ViewModel and they work as expected.
Is it possible to get the datagrid to reflect changes I've made to the bound DataTable using the MVVM pattern?
Is there a datagrid event I can use to refresh the datagrid in the view's code behind?
Thanks for your help!
-Steven
While modifying rows and editing cell contents in the DataTable get reflected in the DataGrid (works for me) you're right that ColumnChanges don't seem to be. If you're using the AutoGenerateColumns option then I imagine it does so at initialization but doesn't watch for changes afterwards.
If you can find an event which fires (I haven't noticed one) when a column is added to the DataTable you could then add it manually in the code behind. Another hack which may or may not be practical would be to set your DataTable propety to null, and then re-set your property to the DataTable, with OnPropertyChanged being called each time. That should force the rebuilding of the DataGrid.
private DataTable _myDataTable;
public DataTable MyDataTable
{
get { return _myDataTable; }
set
{
_myDataTable = value;
OnPropertyChanged("MyDataTable");
}
}
void SomeMethod()
{
....results in column changes
DataTable holder;
holder = MyDataTable
MyDataTable = null;
MyDataTable = holder;
}
You must use ObservableCollection<> type to binding with DataGrid. Until do this, your DataGrid can update the change of DataTable in ViewModel.
Raising the PropertyChanged event seem useless when you bind with the type rather than ObservableCollection<>.
Which event fires when DataGrid's source is updating? I've tried DataContextChanged and SourceUpdated but it never worked out.
Actually I need a simple thing. I want, if there is a new row comes, scroll the GridView's scrollbar down to the bottom to see what it was.
I had the same problem and I manage it this way
DataGrid myGrid = new DataGrid();
CollectionView myCollectionView = (CollectionView)CollectionViewSource.GetDefaultView(myGrid.Items);
((INotifyCollectionChanged)myCollectionView).CollectionChanged += new NotifyCollectionChangedEventHandler(DataGrid_CollectionChanged);
You then need to implement the logic in the event handler DataGrid_CollectionChanged.
Set NotifyOnTargetUpdated = true for the ItemsSource binding and handle TargetUpdated event. If you've multiple bindings, then look for DataTransferEventArgs Property to find out if the target is ItemsSource or not.
If you are trying to have the grid refresh when something is added to the database itself, that's not going to happen. I'm more familiar with WinForms than WPF but I'm assuming there is no magical way to keep a grid in sync with the database without writing some background process that continuously checks for database changes.
If you are updating the actual data source of the grid (ex. Collection) then that will update the grid.
For my part i've used SelectionChange notification which raise each event Del/Add/Edit/Select
It's work very well
private void dataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
Console.WriteLine("hi");
}