Coding the Form Load Event

Visual Studio 6.0

When our form loads, we can configure the BindingCollection.  To do that we add some code to the Form_Load event.

10.  Add the following subroutine to the form's Load event:

Private Sub Form_Load()
With bndPublishers  .DataMember = "Publishers"  Set .DataSource = clsBoundClass 
.Add txtPubID, "Text", "PubID"  .Add txtName, "Text", "Name"
MsgBox "Number of items bound:  " & .Count End With End Sub

What happens here? First, we set the DataMember property of the bndPublishers BindingCollection. Remember the GetDataMember procedure in our class? Well, GetDataMember sets the source of the data for the class. We must provide a unique string because a class might have several DataMembers. Here, again, we are only interested in one – the one that refers to the Publishers table.

Next, the DataSource of the BindingCollection is hooked up to our class, clsBoundClass, which we set as a data provider. Now we can add items to be bound. We are adding our two text boxes to the BindingCollection using its Add method.  The general syntax of the Add method looks like this:

object.Add(object, PropertyName, DataField, DataFormat, Key)

The table shows the options for the bindingCollection's Add method:

Parameter Required/Optional Description
Object Required The control or other data consumer which will be bound. Here we use the names of the two text boxes for each Add.
PropertyName Required The property of the data consumer to which the data field will be bound. We want the Text property of the textboxes to be bound.
DataField Required The column of the data source that will be bound to the property specified in the PropertyName argument. We insert the data field from the Publishers database that we wish to be bound to the text box.
DataFormat Optional A DataFormat object or a reference to a DataFormat variable that will be used to format the bound property.
Key Optional A unique string that identifies the member of the collection.

So we are simply initializing our BindingCollection, then adding the text boxes to the collection. You could add as many as you wish. Again, we wanted to concentrate on the code so we stuck with only two. Next, we interrogate the Count property of the collection and display this in a message box. When we run our program, we should see two bound items (i.e. both of the text boxes we inserted using the Add method).

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