Enter key navigation in DataGridView in relation with Parent-Child Form

Hi,

I am facing a bug while using Enter key for DataGridView (DGV) navigation if the form containing theDGV is an MDI child. However, the code is working well if used from the non-MDI child form.

The problem arises when user presses Enter key on the last column of the last row of DGV to leave the DGV control after typing something (means having cell in edit mode). The focus seems to be left from DGV to the next control which is a Button but then the Enter key doesn't fire the Click event of the Button. However the code is working fine, if the user leaves the DGV pressing Enter but without typing anything on the last cell (means having cell in not edit mode).

Steps to create a sample project:
1. Start New Project with GridEnterNavigation as Name
2. Delete the existing Form1
3. Add new blank form having frmParent as Name
4. Add second new blank form having frmChild as Name
5. Copy the code provided in Listing 1 below to the code file of frmParent form
6. Copy the code provided in Listing2 below to the code file of frmChild form
7. Set the project's startup form as frmParent

Steps to produce a problem:
1. Start the application
2. Click the Open Form button on the Main Form
3. Navigate through the DGV on child form using Enter key
4. Put some data in the last column of the last row and press Enter to end the editing

Now the focus will seemed to be on the button (control next to the DGV) but pressing Enter there will not fire the Click event of the button. However, if you'll leave the last row/last column without modifying it, it would work fine.

However, if you will run the project with the frmChild as the startup form this will work OK.

Listing 1

Public Class frmParent
    Friend WithEvents btnOpenForm As Button

    Private Sub btnOpenForm_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
        Dim frm As New frmChild()
        frm.MdiParent = Me
        frm.StartPosition = FormStartPosition.CenterScreen
        frm.Text = "Child Form"
        frm.Show()
    End Sub

    Private Sub frmParent_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Me.Text = "Main Form"
        Me.WindowState = FormWindowState.Maximized
        Me.IsMdiContainer = True

        CreateControls()
    End Sub

    Private Sub CreateControls()
        btnOpenForm = New System.Windows.Forms.Button
        btnOpenForm.Name = "btnOpenForm"
        btnOpenForm.Text = "Open Form"
        btnOpenForm.TabStop = False
        btnOpenForm.Location = New Point(12, 12)

        AddHandler btnOpenForm.Click, AddressOf btnOpenForm_Click

        Me.Controls.Add(btnOpenForm)
    End Sub

End Class

Listing 2

Public Class frmChild
    Friend WithEvents dgv As GridEnterNavigation.dgvControl
    Friend WithEvents btn As System.Windows.Forms.Button

    Private Sub frmChild_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Me.CreateControls()

        Dim dt As New DataTable()
        dt.Columns.Add(New DataColumn("Name", GetType(String)))
        dt.Columns.Add(New DataColumn("Amount", GetType(Decimal)))

        dt.Rows.Add(dt.NewRow())

        dgv.AllowUserToAddRows = False
        dgv.DataSource = dt
    End Sub

    Private Sub CreateControls()
        '
        'dgv
        '

        Me.dgv = New GridEnterNavigation.dgvControl
        Me.dgv.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize
        Me.dgv.Location = New System.Drawing.Point(12, 12)
        Me.dgv.Name = "dgv"
        Me.dgv.Size = New System.Drawing.Size(268, 204)
        Me.dgv.TabIndex = 0

        '
        'btn
        '
        Me.btn = New System.Windows.Forms.Button
        Me.btn.Location = New System.Drawing.Point(12, 222)
        Me.btn.Name = "btn"
        Me.btn.Size = New System.Drawing.Size(75, 23)
        Me.btn.TabIndex = 1
        Me.btn.Text = "Click"
        Me.btn.UseVisualStyleBackColor = True

        AddHandler btn.Click, AddressOf btn_Click

        Me.Controls.Add(dgv)
        Me.Controls.Add(btn)
    End Sub

    Private Sub btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
        MessageBox.Show("Child Form's Button clicked")
    End Sub

End Class

Public Class dgvControl
    Inherits DataGridView

    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
        MyBase.OnPaint(e)

        'Add your custom paint code here
    End Sub

    Protected Overloads Overrides Function ProcessDialogKey(ByVal keyData As Keys) As Boolean
        'cell is in Edit mode 
        If keyData = Keys.Enter Then
            keyData = Keys.Tab
        End If

        Return MyBase.ProcessDialogKey(keyData)
    End Function

    Protected Overloads Overrides Function ProcessCmdKey(ByRef msg As Message, ByVal keyData As Keys) As Boolean
        'cell is not in Edit mode 
        If keyData = Keys.Enter Then
            keyData = Keys.Tab
            msg.LParam = CType(&HF0001, IntPtr)
            msg.WParam = CType(&H9, IntPtr)

            If Me.CurrentCell.RowIndex = Me.RowCount - 1 And Me.CurrentCell.ColumnIndex = Me.ColumnCount - 1 Then
                Me.FindForm.SelectNextControl(Me, True, True, True, True)
                Return False
            End If
        End If

        Return MyBase.ProcessCmdKey(msg, keyData)
    End Function

End Class

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Enter key navigation in DataGridView in relation with Parent-Child Form

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