C1 Community

i use a data library object in my project. if i change the connection string on the run time i have to end the application and reopen it to access the new data. is it possible to access the data without closing the application?.

i noticed  that when i run the project the CreateSchema event runs one when a dataset needs access to data. if i open a second form with another dataset the CreateSchema not runs again even if i change the connection string, i have to close the application and reopen it to access the new data.

Thanks  for help

Hi,

I don't think that you need to recreate the whole schema just to change
the connection string. You can use the DynamicConnections property
of the C1DataSet to connect a different database. For example, see the
attached sample. Here is some code from that sample.

// switch to the second connection string
Private Sub RadioButton2_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
RadioButton2.CheckedChanged
If RadioButton2.Checked And C1DataSet1.DynamicConnections.Count = 0 Then

Dim conn As Connection = C1DataSet1.Schema.Connections(0).Clone()
conn.ConnectionString = _
"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Program Files\ComponentOne Studio.NET 2.0\common\NWIND.MDB;Persist Security
Info=False"
C1DataSet1.DynamicConnections.Add(conn)
C1DataSet1.Fill()

End If
End Sub

// switch to the first (original) connection string
Private Sub RadioButton1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
RadioButton1.CheckedChanged
If RadioButton1.Checked And C1DataSet1.DynamicConnections.Count > 0 Then

C1DataSet1.DynamicConnections.Clear()
C1DataSet1.Fill()

End If
End Sub

If you still want to recreate the schema you may use the following undocumented trick:

C1DataSet1.SchemaDefComp.SerializedSchema = Nothing

or

C1SchemaDef1.SerializedSchema = Nothing

The schema will be recreated next time when you fill the dataset.

Regards,

-Andrey

Thanks Andrey