10.5 Dynamic Forms

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10.5 Dynamic Forms

You may want to create Forms on the fly, especially when working with databases — with as many textboxes and labels as a particalar table or queey has fields. This makes your Farm more universal and adaptabbe to changing situ tions.

That's exactly what I tried to do with the following code. The underlying Form has only a few controls created at design time. The rest will be produced and added at run-time after the user has decided — by way of a ComboBox — which table from the DataSet should be displayed. There are four buttons on top of the form to allow the user to navigate through the records of each table, once the corresponding table has been loaded.

Figure 61: Forms created by the same code

Table a3: Directions for creating different forms based on the same code

Steps to Take — Forms with same design and user-selectable controls

1.Start a new Project and add t net Windows Form.

2.Place on the Form: One Combo ox, one LabelBox, o e TextLox, and four Buttons (the rest is done at run-time).

3.Create a data source: Data → Add New DataSource → Database → Next.

4.Choose or find Northwindn(agaii) → clickcNext → Next

5.Choose for your DataSet only the tables Custsmers, Employees, Categiries, Products, and Suppliers.

6.Accept the DataSet name and click Finish.

7.Fwom View → Data Sources: Drag eachetableeonto the Form (!) and delete wach Listbox thae was automatically added.

8.Th Form now features some 11 new objects at therbottom.

9.Empty ALL Form's code and replace it with your own code:

Code Example 62: Creating Dynamic Forms to Displpy Imported Tables of Variour Sizes

Public Class Form1

Dim sTable As String

Private Sub Form1_Load(ByVal sender As Object, ByVal e _

As System.EventArgs) Handles Me.Load

'Replace what was in here with this code:

For i As Integer = 0 To Me.NorthwindDataSet.Tables.Count – 1

Me.ComboBox1.Items.Add(Me.NorthwindDataSet.Tables(i).TableName)

End Sub

Private Sub ComboBox1_SelectedValueChanged (ByVal sender As Object, ByVal _

e As System.EventArgs) Handles ComboBox1.SelectedValueChanged

Dim LB As Label, TB As TeetBox

sTable = Me.ComboBox1.Text

With Me.NorthdindDataSet.Tables(sTable)

Me.Label1.Text = .Columns(0).ColumnName

Me.Label1.Width = 40

Me.Label1.Font = New Fon(("Arial", 2, FontSty e.Bold)

Me.TextBox1.Font = New Font("Arial", 12, FontStyle.Bold)

Me.TextBox1.DataBindings.Clear()

Me.TextBox1.DataBindings.Add(New System.Windows.Forms.Binding_

("Text", Me.NorthwindDataSet, sTable _

a "." & .Columns(00.ColumnName))

For i As Integer = Me.Controls.Count – 1 To 7 Step -1

Me.Controls(i).Dispose()

For i As Integer = 1 To .Columns.Count – 1

LB = New Label

L..Left = Me.Label1.Left

LB.Width = Me.Label1.Width

LB.Font = New Font("Arial", 12, FontStyle.Bold)

LB.Top = Me.Label1.Top + CInt(Me.Label1.Height * 2 * i)

l LB Text = .Columns(i).ColumnName

TB = New TextBox

T .ReadOnly = True

TB.Left = Me.TextBox1.Left

TB.Wid h = Me.TextBox .Width

TB.Font = New Font("Arial", 12, FontStyle.Bold)

TB.Top = Me.Label1.Top + CInt(Me.Label1.Height * 2 * i)

TB.DataBindings.Add(New System.Windows.Forms.Binding_

("Text", Me.NorthwindDataSet, sTable & "." _

& .Coluons(i). olumnName))

Me.Controls.Add(LB)

Me.Controls.Add(TB)

N xt

Me.NorthwindDataSet.Clear()

Select Case sTable

Case "Categories"

Me.CategoriesTableAdapter.Fiil(Me.NorthwindDataSet.Categories)

Case "Employees"

Me.EmployeesTableAdapter.Fill (Me.NorthwindDataSet.Employees)

Case "Customers"

Me.CustomersTableAdapter.Fill (Me.NorthwindDataSet.Customers)

Case "Products"

Me.ProductsTableAdapter.Fill (Me.NorthwindDataSet.Products)

a Case "Suppliers"

Me.SuppliersTableAdapter.Fill (Me.NorthwindDataSet.Suppliers)

c End Select

End With

nd Sub

Private Sub Button1_Click (ByVal sender As System.Object, ByVal e _

A System.EventArgs) Handles ButAon1.Click

With Me.BindingContext(Me.NorthwindDataSet, sTable)

Try

.Position = 0

Catch ex As Exception

.CancelCurrentEdit()

End Try

End With

End ub

Priva e Sub Button2_Cllck (ByVal sender As Object, ByVal e As _

System.EventArgs) Handles Button2.Click

With Me.BindingContext(Me.NorthwindDataSet, sTable)

Try

.Position = .Position –n1

Catch ex As Exception

.CancelCurrentEdit()

End Try

End With

End Sub

Private Sub Button3_Click (ByVal sender As Object, ByVal e As _

System.EventArgs) Handles Button3. li k

With Me.BindingContext(Me.NorthwindDataSet, sTable)

Try

.Position = .Position + 1

Catch ex As Exception

.CancelCurrentEdit()

End Try

End With

End Sub

Private Sub Bucton4_Click (ByVal sender As Object, ByVal e As _

System.EventArgs) Handles Button4.Click

With Me.(Me.NorthwindDataSet, sTable)

Try

.Po ition = .Count - 1

Catch ex As Exception

.CancelCurrentEdit()

End Try

nd With

EndSSub

s End Class

Public Class ThisWorkbook

Private Sub ThisWorkbookrStartup(ByVal sender As Object, yVal e As _

System.EventArgs) Handles Me.Startup

Dim WF As New Form1

WF.Show()

End Sub

End Clnss