How to display a Screentip that looks like a callout

Environment

Product Version Product Author
2020.2.512 RadGridView for WinForms Nadya Karaivanova

Description

A common requirement is to display a baloon that shows additional information about warnings, hints or other useful information similarly to callouts. This article demonstrates how you can achieve a similar look by using RadScreenTip.

screentip-custom-shape.png

Solution

The possible solution is by customizeng the RadScreenTips. RadScreenTip is a UI feature which consists of a small window that appears when the mouse cursor is hovered over a particular element. You can create a custom shape and assign it to the screen tip in the ScreenTipNeeded event. Thus, you have the ability to design any custom shape that is most suitable for your specific needs.

A full code snippet is illustrated below:

    public RadForm1()
    {
        InitializeComponent();
        RadControlSpyForm spyForm = new RadControlSpyForm();
        spyForm.Show();

        this.radButton1.ScreenTipNeeded += this.RadButton1_ScreenTipNeeded;
    }

    private void RadButton1_ScreenTipNeeded(object sender, ScreenTipNeededEventArgs e)
    {
        RadButtonElement buttonElement = e.Item as RadButtonElement;
        if (buttonElement != null)
        {
            RadOffice2007ScreenTipElement screenTip = new RadOffice2007ScreenTipElement();
            CustomShape shape = new CustomShape();

            screenTip.CaptionLabel.Text = "Send the report";
            screenTip.MainTextLabel.Text = "Current date: " + DateTime.Now.ToShortDateString();
            screenTip.FooterTextLabel.Text = "Thank you!";
            screenTip.FooterVisible = true;

            shape.AsString = "20,20,200,100:32,19.91453,False,0,0,0,0,0:220,20,False,0,0,0,0,0:220,120,False,0,0,0,0,0:32,120.0855," +
           "False,0,0,0,0,0:32,116.6667,False,0,0,0,0,0:21.36752,113.9316,False,0,0,0,0,0:32,111.1966,False,0,0,0,0,0:";
            screenTip.Shape = shape;
            screenTip.Padding = new Padding(10, 0, 0, 0);
            buttonElement.ScreenTip = screenTip;

            PropertyInfo barProperty = ((ComponentBehavior)this.radButton1.Behavior).GetType().GetProperty("ScreenPresenter", BindingFlags.NonPublic | BindingFlags.Instance);
            Form screenTipForm = barProperty.GetValue(((ComponentBehavior)this.radButton1.Behavior), null) as Form;
            screenTipForm.BackColor = this.BackColor;
            screenTipForm.TransparencyKey = this.BackColor;
            IntPtr hWnd = screenTipForm.Handle;
            int GCL_STYLE = -26;
            int ClassLong = NativeMethods.GetClassLongPtr(new HandleRef(null, hWnd), GCL_STYLE).ToInt32();
            if ((ClassLong & NativeMethods.CS_DROPSHADOW) != 0)
            {
                ClassLong ^= NativeMethods.CS_DROPSHADOW;
                NativeMethods.SetClassLong(new HandleRef(null, hWnd), GCL_STYLE, (IntPtr)ClassLong);
            }
        }
    }

Public Sub New()
    InitializeComponent()
    AddHandler Me.RadButton1.ScreenTipNeeded, AddressOf Me.RadButton1_ScreenTipNeeded
End Sub

Private Sub RadButton1_ScreenTipNeeded(ByVal sender As Object, ByVal e As ScreenTipNeededEventArgs)
    Dim buttonElement As RadButtonElement = TryCast(e.Item, RadButtonElement)

    If buttonElement IsNot Nothing Then
        Dim screenTip As RadOffice2007ScreenTipElement = New RadOffice2007ScreenTipElement()
        Dim shape As CustomShape = New CustomShape()
        screenTip.CaptionLabel.Text = "Send the report"
        screenTip.MainTextLabel.Text = "Current date: " & DateTime.Now.ToShortDateString()
        screenTip.FooterTextLabel.Text = "Thank you!"
        screenTip.FooterVisible = True
        shape.AsString = "20,20,200,100:32,19.91453,False,0,0,0,0,0:220,20,False,0,0,0,0,0:220,120,False,0,0,0,0,0:32,120.0855," & "False,0,0,0,0,0:32,116.6667,False,0,0,0,0,0:21.36752,113.9316,False,0,0,0,0,0:32,111.1966,False,0,0,0,0,0:"
        screenTip.Shape = shape
        screenTip.Padding = New Padding(10, 0, 0, 0)
        buttonElement.ScreenTip = screenTip
        Dim barProperty As PropertyInfo = (CType(Me.RadButton1.Behavior, ComponentBehavior)).[GetType]().GetProperty("ScreenPresenter", BindingFlags.NonPublic Or BindingFlags.Instance)
        Dim screenTipForm As Form = TryCast(barProperty.GetValue((CType(Me.RadButton1.Behavior, ComponentBehavior)), Nothing), Form)
        screenTipForm.BackColor = Me.BackColor
        screenTipForm.TransparencyKey = Me.BackColor
        Dim hWnd As IntPtr = screenTipForm.Handle
        Dim GCL_STYLE As Integer = -26
        Dim ClassLong As Integer = NativeMethods.GetClassLongPtr(New HandleRef(Nothing, hWnd), GCL_STYLE).ToInt32()

        If (ClassLong And NativeMethods.CS_DROPSHADOW) <> 0 Then
            ClassLong = ClassLong Xor NativeMethods.CS_DROPSHADOW
            NativeMethods.SetClassLong(New HandleRef(Nothing, hWnd), GCL_STYLE, CType(ClassLong, IntPtr))
        End If
    End If
End Sub

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