Not very familiar with WPF binding and did not read your source in depth But
I am very familiar with binding in WinForms. The key to binding in WinForms
is that each property of your object should raise the PropertyChanged event
when the value changes. This tells bound controls to update. So a typical
property will look like this:
public string P1
{
get { return p1;}
set
{
if (value == p1)
return;
p1 = value;
OnPropertyChanged("P1");
}
}
The binding to the control will know that it is bound to the P1 property and
update if it receives the PropertyChanged("P1") event.
What is probably happening is that the DataTable columns are not raising the
event correctly when they are updated. Not sure if DataColumn even raises
the event. Likely not.
Try to stay clear of DataTables. They are a huge hassle to use. Rather use
strongly-type objects out of your data access layer.
Louis
-----Original Message-----
From: Kevin Donn [mailto:kd...@msedd.com]
Sent: 02 September 2015 10:35 PM
To: firebird-net-provider@lists.sourceforge.net
Subject: [Firebird-net-provider] WPF/FB Client interaction issue
I've stumbled on either the depth of my own ignorance or a fairly serious
problem when using the Firebird .NET Client in a WPF app. It seems there's
something wrong with the columns that get built during
FbDataAdapter.Fill(DataTable). The columns do not seem to support data
binding properly. Specifically, UI elements don't get updated when values in
the column change. The example code I've provided demonstrates that columns
created prior to Fill and columns created after Fill both work as expected,
but columns created during Fill do not. The example also shows that if you
fill the DataTable from a SQL Server source with everything else kept the
same, columns created during Fill work as expected.
To run the project you'll need to provide some connection string info and
modify the query to return a few rows of string data with a field named
LastName. You may also need to drop in a reference to the Firebird Client
assembly which I removed so as not to send any binaries.
When the interface comes up, alter any value in the third column and tab
away. The expectation is that the value in the fourth column will reflect
the change, but for me it doesn't. I'm running against a 2.1.4 server. If
you alter the value in either the first or second column and tab away, the
other column is updated.
The example project source can be downloaded here:
https://msedd.com/LinkClick.aspx?fileticket=EcRAVG14WA8%3d&portalid=0
I've pasted in the relevant parts below. The MainWindow XAML:
<Window x:Class="FirebirdWPFBug.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation";
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml";
Title="MainWindow" Height="350" Width="525">
<Grid>
<ItemsControl ItemsSource="{Binding COEStudents}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions><ColumnDefinition/><ColumnDefinition/><ColumnDefinit
ion/><ColumnDefinition/></Grid.ColumnDefinitions>
<TextBox Text="{Binding [Foo]}" Grid.Column="0"/>
<TextBox Text="{Binding [Foo]}" Grid.Column="1"/>
<TextBox Text="{Binding [LastName]}" Grid.Column="2"/>
<TextBox Text="{Binding [LastName]}" Grid.Column="3"/>
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>
</Window>
The MainWindow code behind:
namespace FirebirdWPFBug {
public partial class MainWindow: Window {
public MainWindow() {
InitializeComponent();
DataContext=new COEVM();
}
}
public class COEVM {
DataTable coeStudTable;
public DataView COEStudents { get { return coeStudTable.DefaultView; }
}
public COEVM() {
coeStudTable=new DataTable();
// The test is simply to run the project, change a value in the
third column, tab away, and
// note that the fourth column (which is bound to the same
DataColumn) does not update. Making
// a change to the first or second column will cause the other to
update.
// Uncomment these lines to run with SQL Server. You'll need to
point to an existing database and
// provide a query that produces a few rows of data with a column
named LastName.
//System.Data.SqlClient.SqlDataAdapter adapter=
// new System.Data.SqlClient.SqlDataAdapter(
// "select top 3 LastName from HRRM",
// @"Data Source=localhost\SQLEXPRESS;Initial
Catalog=Viewpoint2;Integrated Security=True");
// In the FbConnection below, you'll need to provide a value for
"initial catalog", "user id", and
// "password". You'll also need to provide a query that produces a
few rows of data with a column
// named LastName.
// Comment out these lines to use the SQL Server test above.
FirebirdSql.Data.FirebirdClient.FbConnection conn=new
FirebirdSql.Data.FirebirdClient.FbConnection(
@"dialect=3;charset=NONE;connection lifetime=0;connection
timeout=15;pooling=True;"+
"packet size=8192;initial
catalog=localhost:c:\\Users\\kdonn\\DBs\\NE\\MIS2000.fdb;"+
"server type=Default;user id=userid;password=password");
FirebirdSql.Data.FirebirdClient.FbDataAdapter adapter=
new FirebirdSql.Data.FirebirdClient.FbDataAdapter("select
first 3 LastName from Student", conn);
// Uncomment this line to demonstrate that columns created
*before* Fill work as expected.
//coeStudTable.Columns.Add("LastName", typeof(string));
adapter.Fill(coeStudTable);
// These lines demonstrate that columns created *after* Fill also
work as expected.
coeStudTable.Columns.Add("Foo", typeof(string));
foreach (DataRow r in coeStudTable.Rows)
r["Foo"]=r["LastName"];
// These lines demonstrate that changes are making it from the UI
back to the DataColumn, but
// notification is not making it back out to the UI.
coeStudTable.ColumnChanging+=coeStud_ColumnChanging;
coeStudTable.RowChanging+=coeStud_RowChanging;
}
void coeStud_RowChanging(object sender, DataRowChangeEventArgs e) {
System.Diagnostics.Debug.WriteLine("RowChanging");
}
void coeStud_ColumnChanging(object sender, DataColumnChangeEventArgs
e) {
System.Diagnostics.Debug.WriteLine("ColumnChanging");
}
}
}
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