CTreeViewEdit – A class for enhanced treeview node editing

CTreeViewEdit – A class for enhanced treeview node editing

'-------------------------------------------------------' The CTREEVIEWEDIT Class module'' This class lets you use a regular TextBox control to' edit a treeview node's label. All you have to do to' use this class is adding a TextBox control to the same' form that hosts the TreeView control, and initialize' an instance of the class from inside the form's Load' event. In the following example we have a treeview' control named tvwHierarchy and a support textbox control' named txtSupport'  Dim TVEdit As New CTreeViewEdit''  Private Sub Form_Load()'      TVEdit.Init tvwHierarchy, txtSupport'  End Sub' You can then write code in the event procs of txtSupport,' as you would do with a regular textbox. For example you' can filter out invalid keys. You can also terminate the' edit mode by invoking the class's EndLabelEdit method' (pass True to accept the new value, False to reject it)'Private Sub txtSupport_KeyPress(KeyAscii As Integer)'    If KeyAscii >= 48 And KeyAscii <= 57 Then'        ' filter out numeric keys'        KeyAscii = 0'    ElseIf KeyAscii = 8 Then'        ' the backspace cancels the operation'        TVEdit.EndLabelEdit False'    End If'End Sub'-------------------------------------------------------'-------------------------------------------------------' API Declares'-------------------------------------------------------Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal _    hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _    lParam As Any) As LongPrivate Declare Function GetClientRect Lib "user32" (ByVal hWnd As Long, _    lpRect As RECT) As LongPrivate Declare Function SetCapture Lib "user32" (ByVal hWnd As Long) As LongPrivate Declare Function ReleaseCapture Lib "user32" () As LongPrivate Type RECT    Left As Long    Top As Long    Right As Long    Bottom As LongEnd TypePrivate Const TV_FIRST = &H1100Private Const TVM_GETITEMRECT = (TV_FIRST + 4)Private Const TVM_GETNEXTITEM = (TV_FIRST + 10)Private Const TVGN_CARET = 9'-------------------------------------------------------' module variables'-------------------------------------------------------' the TreeView controlDim WithEvents TreeView As TreeView' the hidden textbox controlDim WithEvents TextBox As TextBox' the parent form (can be anything)Dim Parent As Object' these variables are active when the user is editing the node label' the previous value of the Node's Text propertyDim saveText As String' the control that had Default = TrueDim defaultCtrl As Object' the control that had Cancel = TrueDim cancelCtrl As Object' Initialize this instanceSub Init(TView As TreeView, TBox As TextBox)    Set TreeView = TView    Set TextBox = TBox    Set Parent = TextBox.Parent    TextBox.Visible = FalseEnd Sub'-------------------------------------------------------' event procedures'-------------------------------------------------------' when the user clicks on a treeview's item' this procedure gets the control and cancels' the default operationPrivate Sub TreeView_BeforeLabelEdit(Cancel As Integer)    Cancel = True    StartLabelEditEnd Sub' when the user types in the textbox, grow or shrink itPrivate Sub TextBox_Change()    Dim saveFont As StdFont    Dim wi As Single    Dim borderWidth As Single        ' temporarily change the parent form's font,    ' to use its TextWidth method    Set saveFont = Parent.Font    Set Parent.Font = TextBox.Font    wi = Parent.TextWidth(TextBox.Text) + Parent.ScaleX(20, vbPixels, _        Parent.ScaleMode)    Set Parent.Font = saveFont    ' this is the Treeview's border, in the same coordinate    ' system as the parent form    borderWidth = Parent.ScaleX(2, vbPixels, Parent.ScaleMode)        ' don't let the textbox grow larger than the treeview    If TextBox.Left + wi > TreeView.Left + TreeView.Width - borderWidth Then        wi = TreeView.Left + TreeView.Width - TextBox.Left - borderWidth    End If        TextBox.Width = wi    End Sub' terminate the edit mode when the user types' Enter or Escape keysPrivate Sub TextBox_KeyPress(KeyAscii As Integer)    Select Case KeyAscii        Case 13            EndLabelEdit True            KeyAscii = 0        Case 27            EndLabelEdit False            KeyAscii = 0    End SelectEnd Sub' terminate the edit mode when the user clicks' outside of the textbox controlPrivate Sub TextBox_MouseDown(Button As Integer, Shift As Integer, X As Single, _    Y As Single)    If X < 0 Or Y < 0 Or X > TextBox.Width Or Y > TextBox.Height Then        EndLabelEdit True    End IfEnd Sub'-------------------------------------------------------' Support routines'-------------------------------------------------------' enter edit modePrivate Sub StartLabelEdit()    ' get the edit rectangle for the selected item    Dim lpRect As RECT, lpClientRect As RECT    Dim hNode As Long        ' get the handle of the selected node    hNode = SendMessage(TreeView.hWnd, TVM_GETNEXTITEM, TVGN_CARET, ByVal 0&)    ' get the bounding rectangle for this node    ' the function expects in input the handle of the item    ' at the beginning of the RECT structure    lpRect.Left = hNode    If SendMessage(TreeView.hWnd, TVM_GETITEMRECT, True, lpRect) = 0 Then        ' a zero value means error        Exit Sub    End If    ' convert coordinates into form coordinates    With lpRect        .Left = TreeView.Left + Parent.ScaleX(.Left, vbPixels, Parent.ScaleMode)        .Top = TreeView.Top + Parent.ScaleY(.Top, vbPixels, Parent.ScaleMode)        .Right = TreeView.Left + Parent.ScaleX(.Right, vbPixels, _            Parent.ScaleMode)        .Bottom = TreeView.Top + Parent.ScaleY(.Bottom, vbPixels, _            Parent.ScaleMode)    End With        ' move the textbox in front of the TreeView    With TextBox        ' move the textbox in the right position        .Move lpRect.Left, lpRect.Top, lpRect.Right - lpRect.Left + 200, _            lpRect.Bottom - lpRect.Top        .ZOrder                ' transfer the node's text to the TextBox control        .Text = TreeView.SelectedItem.Text        .SelStart = 0        .SelLength = Len(.Text)        Set .Font = TreeView.Font                ' make the textbox visible and give it the focus        .Visible = True        .SetFocus                ' grab the mouse capture        SetCapture .hWnd                ' disable any button with Default or Cancel property        ' this is necessary because we want to trap the Enter        ' and Cancel keys while the user is editing the        ' node's label.        Set defaultCtrl = Nothing        Set cancelCtrl = Nothing        Dim ctrl As Control                On Error Resume Next                For Each ctrl In Parent.Controls            If ctrl.Default = False Then                ' not supported or Default = False            Else                Set defaultCtrl = ctrl                ctrl.Default = False            End If            If ctrl.Cancel = False Then                ' not supported or Cancel = False            Else                Set cancelCtrl = ctrl                ctrl.Cancel = False            End If        Next            ' save node's text, then clear it - this is necessary to avoid the         ' original        ' text appears if the editing textbox shrinks        saveText = TreeView.SelectedItem.Text        TreeView.SelectedItem.Text = ""        End WithEnd Sub' this procedure is called from TextBox event procs' or by the client applicationSub EndLabelEdit(AcceptIt As Boolean)    If AcceptIt Then        ' if not canceled, assign the text to the underlying node        TreeView.SelectedItem.Text = TextBox.Text    Else        ' else restore original text        TreeView.SelectedItem.Text = saveText    End If    ' release mouse capture, and restore form's font    ReleaseCapture        ' make the TextBox invisible and clear it    TextBox.Visible = False    TextBox.Text = ""    TreeView.SetFocus        ' restore Default and Cancel buttons, if any    On Error Resume Next    defaultCtrl.Default = True    cancelCtrl.Cancel = TrueEnd Sub

devx-admin

devx-admin

Share the Post:
Clean Energy Adoption

Inside Michigan’s Clean Energy Revolution

Democratic state legislators in Michigan continue to discuss and debate clean energy legislation in the hopes of establishing a comprehensive clean energy strategy for the

Chips Act Revolution

European Chips Act: What is it?

In response to the intensifying worldwide technology competition, Europe has unveiled the long-awaited European Chips Act. This daring legislative proposal aims to fortify Europe’s semiconductor

Revolutionized Low-Code

You Should Use Low-Code Platforms for Apps

As the demand for rapid software development increases, low-code platforms have emerged as a popular choice among developers for their ability to build applications with

Global Layoffs

Tech Layoffs Are Getting Worse Globally

Since the start of 2023, the global technology sector has experienced a significant rise in layoffs, with over 236,000 workers being let go by 1,019

Clean Energy Adoption

Inside Michigan’s Clean Energy Revolution

Democratic state legislators in Michigan continue to discuss and debate clean energy legislation in the hopes of establishing a comprehensive clean energy strategy for the state. A Senate committee meeting

Chips Act Revolution

European Chips Act: What is it?

In response to the intensifying worldwide technology competition, Europe has unveiled the long-awaited European Chips Act. This daring legislative proposal aims to fortify Europe’s semiconductor supply chain and enhance its

Revolutionized Low-Code

You Should Use Low-Code Platforms for Apps

As the demand for rapid software development increases, low-code platforms have emerged as a popular choice among developers for their ability to build applications with minimal coding. These platforms not

Cybersecurity Strategy

Five Powerful Strategies to Bolster Your Cybersecurity

In today’s increasingly digital landscape, businesses of all sizes must prioritize cyber security measures to defend against potential dangers. Cyber security professionals suggest five simple technological strategies to help companies

Global Layoffs

Tech Layoffs Are Getting Worse Globally

Since the start of 2023, the global technology sector has experienced a significant rise in layoffs, with over 236,000 workers being let go by 1,019 tech firms, as per data

Huawei Electric Dazzle

Huawei Dazzles with Electric Vehicles and Wireless Earbuds

During a prominent unveiling event, Huawei, the Chinese telecommunications powerhouse, kept quiet about its enigmatic new 5G phone and alleged cutting-edge chip development. Instead, Huawei astounded the audience by presenting

Cybersecurity Banking Revolution

Digital Banking Needs Cybersecurity

The banking, financial, and insurance (BFSI) sectors are pioneers in digital transformation, using web applications and application programming interfaces (APIs) to provide seamless services to customers around the world. Rising

FinTech Leadership

Terry Clune’s Fintech Empire

Over the past 30 years, Terry Clune has built a remarkable business empire, with CluneTech at the helm. The CEO and Founder has successfully created eight fintech firms, attracting renowned

The Role Of AI Within A Web Design Agency?

In the digital age, the role of Artificial Intelligence (AI) in web design is rapidly evolving, transitioning from a futuristic concept to practical tools used in design, coding, content writing

Generative AI Revolution

Is Generative AI the Next Internet?

The increasing demand for Generative AI models has led to a surge in its adoption across diverse sectors, with healthcare, automotive, and financial services being among the top beneficiaries. These

Microsoft Laptop

The New Surface Laptop Studio 2 Is Nuts

The Surface Laptop Studio 2 is a dynamic and robust all-in-one laptop designed for creators and professionals alike. It features a 14.4″ touchscreen and a cutting-edge design that is over

5G Innovations

GPU-Accelerated 5G in Japan

NTT DOCOMO, a global telecommunications giant, is set to break new ground in the industry as it prepares to launch a GPU-accelerated 5G network in Japan. This innovative approach will

AI Ethics

AI Journalism: Balancing Integrity and Innovation

An op-ed, produced using Microsoft’s Bing Chat AI software, recently appeared in the St. Louis Post-Dispatch, discussing the potential concerns surrounding the employment of artificial intelligence (AI) in journalism. These

Savings Extravaganza

Big Deal Days Extravaganza

The highly awaited Big Deal Days event for October 2023 is nearly here, scheduled for the 10th and 11th. Similar to the previous year, this autumn sale has already created

Cisco Splunk Deal

Cisco Splunk Deal Sparks Tech Acquisition Frenzy

Cisco’s recent massive purchase of Splunk, an AI-powered cybersecurity firm, for $28 billion signals a potential boost in tech deals after a year of subdued mergers and acquisitions in the

Iran Drone Expansion

Iran’s Jet-Propelled Drone Reshapes Power Balance

Iran has recently unveiled a jet-propelled variant of its Shahed series drone, marking a significant advancement in the nation’s drone technology. The new drone is poised to reshape the regional

Solar Geoengineering

Did the Overshoot Commission Shoot Down Geoengineering?

The Overshoot Commission has recently released a comprehensive report that discusses the controversial topic of Solar Geoengineering, also known as Solar Radiation Modification (SRM). The Commission’s primary objective is to

Remote Learning

Revolutionizing Remote Learning for Success

School districts are preparing to reveal a substantial technological upgrade designed to significantly improve remote learning experiences for both educators and students amid the ongoing pandemic. This major investment, which

Revolutionary SABERS Transforming

SABERS Batteries Transforming Industries

Scientists John Connell and Yi Lin from NASA’s Solid-state Architecture Batteries for Enhanced Rechargeability and Safety (SABERS) project are working on experimental solid-state battery packs that could dramatically change the

Build a Website

How Much Does It Cost to Build a Website?

Are you wondering how much it costs to build a website? The approximated cost is based on several factors, including which add-ons and platforms you choose. For example, a self-hosted

Battery Investments

Battery Startups Attract Billion-Dollar Investments

In recent times, battery startups have experienced a significant boost in investments, with three businesses obtaining over $1 billion in funding within the last month. French company Verkor amassed $2.1

Copilot Revolution

Microsoft Copilot: A Suit of AI Features

Microsoft’s latest offering, Microsoft Copilot, aims to revolutionize the way we interact with technology. By integrating various AI capabilities, this all-in-one tool provides users with an improved experience that not

AI Girlfriend Craze

AI Girlfriend Craze Threatens Relationships

The surge in virtual AI girlfriends’ popularity is playing a role in the escalating issue of loneliness among young males, and this could have serious repercussions for America’s future. A

AIOps Innovations

Senser is Changing AIOps

Senser, an AIOps platform based in Tel Aviv, has introduced its groundbreaking AI-powered observability solution to support developers and operations teams in promptly pinpointing the root causes of service disruptions