[RESOLVED] I need to non-modal form to act modally

All of my forms are MDI children. I have one form that is collecting input parameters for a report. One of the parameters needs to come from another form. For the life of me, I can't get it to work.

Code:

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        If Trim(Vendor) = "Y" Then
        Else
            '------------must select a vendor
            glbPart = "GetAVendor"
            frmVendorList.Show()
            '-- we now have something in glbvendor
            MsgBox(glbVendor)
        End If

---

I have to message box code just to verify the selection. glbPart is just a hand off parameter to tell the frmVendorList code to come back to this form rather than where it was origianlly programmed to go.

I tried a do until glbVendor <> "", but that put me into a death loop and I never got to select a vendor from the vendor list form. Obviously, the easiest would be if I could make frmVendorList Modal, but I can't see how to do that once it's been created modally.

Any ideas?

Can you just add a vendor list drop down to the form gathering the parameters rather than having the parameter gathering form open up the vendor list form?

ShowDialog() displays a form modally. Use that instead of Show().

Hack: The code asks a series of questions. One of them is 'one vendor or all'. If they choose 'all', no problem. But, if the choose a specific vendor, I need to give them a form listing all the vendors. I have one (frmvendorlist). The problem is, I call it and the code in the calling form continues merrily along. I need to have it stop until it gets a value from the other form.

Sitten: I can't use ShowDialog() on a child form. Already tried it.

If they choose vendor why do you need to give them a form? All they are choosing is vendor name right? Can't you populate a dropdown with that?

Your non-modal form may not be able to show a modal form, but it CAN call a method on the MDI parent that shows a modal form and returns the response. It would be the same as having it call a method in a module that shows a modal form and returns something, except that by having the method be part of the parent form it would be more in keeping with the spirit of object orientation.

HACK: I am using input boxes

Code:

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        Vendor = InputBox("Select all vendors, [Y] or [N]?", , "Y")
        If Trim(Vendor) = "" Then Exit Sub
        Vendor = Vendor.ToUpper

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Shaggy: I bow to your knowledge, as it far exceeds mine. I will try to understand what you just said. :-)

The fact that it didn't allow you to call ShowDialog on the form frmVendorList is because you're using the default form instance which has been set to be a mid child form. The solution is quite simple: create a new instance of the frmVendorList form and showdialog it.

Code:

---

If Trim(Vendor) = "Y" Then
        Else
            '------------must select a vendor
            glbPart = "GetAVendor"
            Dim vendorLst as New frmVendorList()
            If vendorLst.ShowDialog() = Windows.Forms.DialogResult.OK Then
                '-- we now have something in glbvendor
                MsgBox(glbVendor)
            End If
        End If

---

I still get this error:

Form that is not a top-level form cannot be displayed as a modal dialog box. Remove the form from any parent form before calling showDialog.

Quote:

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Originally Posted by Pasvorto

I still get this error:

Form that is not a top-level form cannot be displayed as a modal dialog box. Remove the form from any parent form before calling showDialog.

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Did you do as shown in my last post (creating a new instance of the form)?

Copied it exactly

If this was still in VB6 I would just make the form a non-child. I don't see how to do that in .NET

I bet there's some code that's running in the constructor that's attaching it to the mdi parent...

-tg

Do you set the form mdiParent property at form load? In other words, how do you display frmVendorList as an mid child form from the mdi parent form?

Quote:

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Originally Posted by techgnome

I bet there's some code that's running in the constructor that's attaching it to the mdi parent...

-tg

---

That's what I'm suspecting too.

I am not doing anything consciously. I think when I created it, it was created as a child.

Found this:

<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> Partial Class frmVendorList
#Region "Windows Form Designer generated code "
<System.Diagnostics.DebuggerNonUserCode()> Public Sub New()
MyBase.New()
'This call is required by the Windows Form Designer.
InitializeComponent()
'This form is an MDI child.
'This code simulates the VB6
' functionality of automatically
' loading and showing an MDI
' child's parent.
Me.MDIParent = VENDOR.MDIForm1
VENDOR.MDIForm1.Show
End Sub

I commented these out and it seems to work

Me.MDIParent = VENDOR.MDIForm1
VENDOR.MDIForm1.Show


Are there any traps to doing that?

Can you show the constructor of frmVendorList class and probably the frmVendorList_Load event hander too (if it has one)? What you described is not the normal, default behavior of forms in .Net. There must be code somewhere that change the default behavior to what it is now... We need to find out where that code is in order to find a way to work with it.

Code:

---

<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> Partial Class frmVendorList
#Region "Windows Form Designer generated code "
        <System.Diagnostics.DebuggerNonUserCode()> Public Sub New()
                MyBase.New()
                'This call is required by the Windows Form Designer.
                InitializeComponent()
                'This form is an MDI child.
                'This code simulates the VB6
                ' functionality of automatically
                ' loading and showing an MDI
                ' child's parent.
        Me.MdiParent = VENDOR.MDIForm1
        VENDOR.MDIForm1.Show()
        End Sub
        'Form overrides dispose to clean up the component list.
        <System.Diagnostics.DebuggerNonUserCode()> Protected Overloads Overrides Sub Dispose(ByVal Disposing As Boolean)
                If Disposing Then
                        If Not components Is Nothing Then
                                components.Dispose()
                        End If
                End If
                MyBase.Dispose(Disposing)
        End Sub
        'Required by the Windows Form Designer
        Private components As System.ComponentModel.IContainer
        Public ToolTip1 As System.Windows.Forms.ToolTip
        Public WithEvents fGrid1 As AxMSFlexGridLib.AxMSFlexGrid
    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.
    'Do not modify it using the code editor.
        <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.components = New System.ComponentModel.Container
        Dim resources As System.ComponentModel.ComponentResourceManager = New System.ComponentModel.ComponentResourceManager(GetType(frmVendorList))
        Me.ToolTip1 = New System.Windows.Forms.ToolTip(Me.components)
        Me.fGrid1 = New AxMSFlexGridLib.AxMSFlexGrid
        CType(Me.fGrid1, System.ComponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        '
        'fGrid1
        '
        Me.fGrid1.Location = New System.Drawing.Point(8, 5)
        Me.fGrid1.Name = "fGrid1"
        Me.fGrid1.OcxState = CType(resources.GetObject("fGrid1.OcxState"), System.Windows.Forms.AxHost.State)
        Me.fGrid1.Size = New System.Drawing.Size(423, 219)
        Me.fGrid1.TabIndex = 1
        '
        'frmVendorList
        '
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 14.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.BackColor = System.Drawing.SystemColors.Control
        Me.ClientSize = New System.Drawing.Size(441, 236)
        Me.Controls.Add(Me.fGrid1)
        Me.Cursor = System.Windows.Forms.Cursors.Default
        Me.Font = New System.Drawing.Font("Arial", 8.0!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Icon = CType(resources.GetObject("$this.Icon"), System.Drawing.Icon)
        Me.Location = New System.Drawing.Point(134, 104)
        Me.MaximizeBox = False
        Me.Name = "frmVendorList"
        Me.RightToLeft = System.Windows.Forms.RightToLeft.No
        Me.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen
        Me.Text = "Vendor List"
        CType(Me.fGrid1, System.ComponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)

    End Sub
#End Region
End Class

---

Quote:

---

Originally Posted by Pasvorto

I commented these out and it seems to work

Me.MDIParent = VENDOR.MDIForm1
VENDOR.MDIForm1.Show


Are there any traps to doing that?

---

There it is... Yes, you can and should take out those lines. Basically it set the mdiparent of the form as soon as an instance of the form is created. You don't want that. You can always set it manually when you want to, which affects only the current instance that you're working on.
Since you take that code out of the contructor, you will need to assign the mid parent to the form whenever you want to make it an mid child form.

Is this what you mean?

Code:

---

Private Sub frmVendorList_Load(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles MyBase.Load
        Try

            Me.Width = 447
            Me.Height = 261
            'set grid headings
            fGrid1.Row = 0
            fGrid1.Col = 0
            fGrid1.Text = "Account #"
            fGrid1.set_ColWidth(0, 1000)
            fGrid1.set_ColAlignment(0, 1)
            fGrid1.Col = 1
            fGrid1.Text = "Vendor"
            fGrid1.set_ColWidth(1, 3500)
            fGrid1.Redraw = False
            '
            'now fill grid
            '
            Using cnxn As New SqlClient.SqlConnection(cnxnstring)
                cnxn.Open()
                Using sql As New SqlClient.SqlCommand("SELECT [ACCOUNT],[NAME] FROM VENDOR ORDER BY [NAME]")
                    sql.Connection = cnxn
                    sql.CommandType = CommandType.Text
                    Dim reader As SqlDataReader
                    reader = sql.ExecuteReader
                    Using reader
                        If reader.HasRows Then
                            fGrid1.Row = 1
                            While reader.Read
                                fGrid1.Col = 0
                                fGrid1.Text = reader("ACCOUNT") & ""
                                fGrid1.Col = 1
                                fGrid1.Text = reader("Name") & ""
                                If Trim(fGrid1.Text) <> "" Then
                                    fGrid1.Rows = fGrid1.Rows + 1
                                    fGrid1.Row = fGrid1.Row + 1
                                End If
                            End While
                        End If
                    End Using
                End Using
            End Using
            '===============

            If fGrid1.Rows > 2 Then fGrid1.Rows = fGrid1.Rows - 1
            fGrid1.Redraw = True

            System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default

        Catch ex As Exception
            System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default
            MsgBox("An error occurred: [" & Err.Number & "] " & Err.Description & " - Source: (frmVendorList)Form_Load")
        End Try

    End Sub

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Cool. Thanks guys. Someday, my VB6 head will get wrapped around this VB.Net code :-)

The frmVendorList_Load event handler looks fine. No problem there.

By the way, try to stay away from default form instances... Although they are convenient, they create more headaches than they're worth. Just create an instance of a form manually when you want to, it only takes 1 extra line of code yet you can avoid many potential problems in the long run, especially when your app is multi-threaded.
So in stead of doing this to show Form1

Code:

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Form1.Show()

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You should always create an instance of Form1 yourself and show it as below

Code:

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Dim frm1 as New Form1
frm1.Show()

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doing what? setting the mdi parent in the constructor? Yes... as you just found out... also you're using the default instance of the mdiparent...

I'd make two constructors... one parameter-less that calls initialize component, mybase and all that... and a second that takes a parameter of type form... calls mybase, initialize components, then sets the mdi parent property to the passed in form instance... and that's it... I wouldn't even let it show the parent form... it should already be showing.

-tg

edit - and that's what I get for leaving the window open too long before hitting reply....

So much to learn... so little grey matter to learn with :-P