Tag: Uncategorized
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Binding SelectedItem to ItemsSource between two datagrids
A recent problem I had was to bind the SelectedItem from a master datagrid, to the ItemsSource of a child datagrid. My work around’s using mouse clicks had too many limitations when used with MVVM – delete the selected item from the parent collection, the child collection did not update. Whilst watching John Papas PDC video for building large scale Silverlight application I spotted his sweet DataGridRowSelected command behaviours (documented http://thoughtjelly.blogspot.com/2009/12/silverlight-commands-data-grid-row.html)
To implement this you can do the following, XAML:
<UserControl x:Class="NestedDataGrid.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"
xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"
xmlns:this="clr-namespace:NestedDataGrid"
xmlns:commands="clr-namespace:Microsoft.Practices.Composite.Presentation.Commands;assembly=Microsoft.Practices.Composite.Presentation"
>
<data:DataGrid x:Name="dgTeams"
SelectedItem="{Binding SelectedTeam}"
ItemsSource="{Binding Teams}"
this:DataGridRowSelected.Command="{Binding GridViewRowSelectedCommand}"
/>
<Button Content="Delete Current"
commands:Click.Command="{Binding DeleteCurrentTeamCommand}"
commands:Click.CommandParameter="{Binding SelectedTeam}"
/>
Code behind:
public partial class MainPage : UserControl
{
ViewModel viewModel = new ViewModel();
public MainPage()
{
InitializeComponent();
this.LayoutRoot.DataContext = viewModel;
}
}and ViewModel:
public class ViewModel: ObjectBase
{
ObservableCollection _rainbowPeeps;
ObservableCollection _theSimpsons;
ObservableCollection _familyGuyKids;
public ViewModel()
{
/// setting up some dummy data
_rainbowPeeps = new ObservableCollection()
{
new Person(){ PersonId=1, Name="George"},
new Person(){ PersonId=2, Name="Zippy"},
new Person(){ PersonId=3, Name="Bungle"},
};
_theSimpsons = new ObservableCollection()
{
new Person(){ PersonId=4, Name="Moe"},
new Person(){ PersonId=5, Name="Barney"},
new Person(){ PersonId=6, Name="Selma"},
};
_familyGuyKids = new ObservableCollection()
{
new Person(){ PersonId=7, Name="Stewie"},
new Person(){ PersonId=8, Name="Meg"},
new Person(){ PersonId=9, Name="Chris"},
};
Teams = new ObservableCollection()
{
new Team(){ TeamId=1, TeamDesc="Rainbow", People=_rainbowPeeps},
new Team(){ TeamId=2, TeamDesc="Simpsons", People=_theSimpsons},
new Team(){ TeamId=3, TeamDesc="Family Guys", People=_familyGuyKids },
};
/// COMMAND IMPLEMENTATIONS. The DataGridRowSelected parameter
/// is the datacontext of the selected row.
GridViewRowSelectedCommand = new DelegateCommand(
delegate(Team team) { SelectedTeam = team; }
);
DeleteCurrentTeamCommand = new DelegateCommand(
delegate(Team team)
{
Teams.Remove(team);
if (Teams.Count > 0)
SelectedTeam = Teams[0];
else
SelectedTeam = null;
}
);
}
private ObservableCollection _teams;
public ObservableCollection Teams
{
get { return _teams; }
set
{
SetValue(ref _teams, value, "Teams");
}
}
private Team _selectedTeam;
public Team SelectedTeam
{
get { return _selectedTeam; }
set
{
SetValue(ref _selectedTeam, value, "SelectedTeam");
}
}
///
/// Command to handle the selection of a row.
///
private DelegateCommand _gridViewRowSelectedCommand;
public DelegateCommand GridViewRowSelectedCommand
{
get { return _gridViewRowSelectedCommand; }
set
{
SetValue(ref _gridViewRowSelectedCommand, value, "GridViewRowSelectedCommand");
}
}
///
/// Used to simulate the deletion of a parent team
///
private DelegateCommand _deleteCurrentTeamCommand;
public DelegateCommand DeleteCurrentTeamCommand
{
get { return _deleteCurrentTeamCommand; }
set
{
SetValue(ref _deleteCurrentTeamCommand, value, "DeleteCurrentTeamCommand");
}
}
}Finally, some misc data classes and the ObjectBase super class for INotifyPropertyChanged:
public abstract class ObjectBase : Object, INotifyPropertyChanged
{
public ObjectBase()
{ }
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void _OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler pceh = PropertyChanged;
if (pceh != null)
{
pceh(this, new PropertyChangedEventArgs(propertyName));
}
}
protected virtual bool SetValue(ref T target, T value, string propertyName)
{
if (Object.Equals(target, value))
{
return false;
}
target = value;
_OnPropertyChanged(propertyName);
return true;
}
}
public class Person: ObjectBase
{
private int _personId;
public int PersonId
{
get { return _personId; }
set
{
SetValue(ref _personId, value, "PersonId");
}
}
private string _name;
public string Name
{
get { return _name; }
set
{
SetValue(ref _name, value, "Name");
}
}
}
public class Team : ObjectBase
{
private int _teamId;
public int TeamId
{
get { return _teamId; }
set
{
SetValue(ref _teamId, value, "TeamId");
}
}
private string _teamDesc;
public string TeamDesc
{
get { return _teamDesc; }
set
{
SetValue(ref _teamDesc, value, "TeamDesc");
}
}
private ObservableCollection _people;
public ObservableCollection People
{
get { return _people; }
set
{
SetValue(ref _people, value, "People");
}
}
public override string ToString()
{
return _teamId.ToString() + " " + _teamDesc;
}
}Brilliant 🙂
NOTE: Code for DataGridRowSelected and DataGridRowSelectedCommandBehaviour is here
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Debugging SQL2005 Stored Procedures from VS2008
Yesterday I was having great success debugging T-SQL SP’s from VS2008 to a local developer SQL server. This was easy to do:
- Enable SQL debugging in all my VS2008 projects (all of them was probably overkill, but it works)
- Turn-off the local windows firewall (again overkill, but it works)
- Create a connection to a database
- Right click the SP | Open
- Set a breakpoint.
- Launch the app in debug mode.
All was good and this worked as expected without the need to create loads of PRINT statements and having all the power of the VS debugging tools.
…Then VS crashed… And it all stopped working. Totally stopped. Totally confused. No manner of reboots, resets, alterations to config made any difference.
After some considerable support from Microsoft the solution was to delete all the Program Debug Database (.pdb) files in the solutions and rebuild… and voila.
So the moral is – if VS crashes whilst debugging – delete the PDB’s – they might, just might, be corrupt and causing you a whole world of pain.
Here endeth the lesson…
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Determining Users in an AD Group
From a command line (on the AD server) you can use this to get the members of a group:
1: dsquery group -name "Group Account Name" | dsget group -membersAdditionally a command line exe to get the groups for the logged in member too, something like this:
1: My.User.InitializeWithWindowsUser()
2:
3: Dim identity As System.Security.Principal.WindowsIdentity = TryCast(My.User.CurrentPrincipal.Identity, System.Security.Principal.WindowsIdentity)
4:
5: Debug.WriteLine(identity.Name)
6:
7: For Each group As System.Security.Principal.SecurityIdentifier In identity.Groups()
8: Debug.WriteLine(group.Translate(GetType(System.Security.Principal.NTAccount)), "group")
9: Next
10:
Mark Cooper 