Only dock form once

[meraj]

How can I ensure that a Form that has been docked to an MDIForm doesn't get docked a 2nd time?  That is, I need a Form to only be visible once.  I tried making it a singleton class, but calling the DockControl of the RadDock still added a same form , though one was an empty shell.

[Richard Slade]

Hello Meraj,

Please have a look at this forum post which explains a few options in detail.
Hope that helps
Richard

[meraj]

Hi Richard,
My scenario is that i have a MDI form with menu and i am opening the form as per menu click .

[Richard Slade]

Hello Meraj,

Here is a full exmaple for you using a MainForm (MDI Parent) and two child forms.
Hope this helps

Main.Designer.cs

namespace RadControlsWinFormsApp1
{
    partial class Main
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.radMenu1 = new Telerik.WinControls.UI.RadMenu();
            this.radMenuItem1 = new Telerik.WinControls.UI.RadMenuItem();
            this.radDock1 = new Telerik.WinControls.UI.Docking.RadDock();
            this.documentContainer1 = new Telerik.WinControls.UI.Docking.DocumentContainer();
            this.radMenuItem2 = new Telerik.WinControls.UI.RadMenuItem();
            ((System.ComponentModel.ISupportInitialize)(this.radMenu1)).BeginInit();
            ((System.ComponentModel.ISupportInitialize)(this.radDock1)).BeginInit();
            this.radDock1.SuspendLayout();
            ((System.ComponentModel.ISupportInitialize)(this.documentContainer1)).BeginInit();
            this.SuspendLayout();
            //
            // radMenu1
            //
            this.radMenu1.Items.AddRange(new Telerik.WinControls.RadItem[] {
            this.radMenuItem1,
            this.radMenuItem2});
            this.radMenu1.Location = new System.Drawing.Point(0, 0);
            this.radMenu1.Name = "radMenu1";
            this.radMenu1.Size = new System.Drawing.Size(548, 20);
            this.radMenu1.TabIndex = 1;
            this.radMenu1.Text = "radMenu1";
            //
            // radMenuItem1
            //
            this.radMenuItem1.Name = "radMenuItem1";
            this.radMenuItem1.Text = "Launch Child Form";
            this.radMenuItem1.Click += new System.EventHandler(this.radMenuItem1_Click);
            //
            // radDock1
            //
            this.radDock1.AutoDetectMdiChildren = true;
            this.radDock1.Controls.Add(this.documentContainer1);
            this.radDock1.Dock = System.Windows.Forms.DockStyle.Fill;
            this.radDock1.DocumentManager.DocumentInsertOrder = Telerik.WinControls.UI.Docking.DockWindowInsertOrder.InFront;
            this.radDock1.IsCleanUpTarget = true;
            this.radDock1.Location = new System.Drawing.Point(0, 20);
            this.radDock1.MainDocumentContainer = this.documentContainer1;
            this.radDock1.Name = "radDock1";
            this.radDock1.Padding = new System.Windows.Forms.Padding(5);
            //
            //
            //
            this.radDock1.RootElement.MinSize = new System.Drawing.Size(25, 25);
            this.radDock1.Size = new System.Drawing.Size(548, 424);
            this.radDock1.SplitterWidth = 4;
            this.radDock1.TabIndex = 2;
            this.radDock1.TabStop = false;
            this.radDock1.Text = "radDock1";
            //
            // documentContainer1
            //
            this.documentContainer1.Location = new System.Drawing.Point(5, 5);
            this.documentContainer1.Name = "documentContainer1";
            //
            //
            //
            this.documentContainer1.RootElement.MinSize = new System.Drawing.Size(25, 25);
            this.documentContainer1.Size = new System.Drawing.Size(538, 414);
            this.documentContainer1.SizeInfo.SizeMode = Telerik.WinControls.UI.Docking.SplitPanelSizeMode.Fill;
            this.documentContainer1.SplitterWidth = 4;
            this.documentContainer1.TabIndex = 0;
            this.documentContainer1.TabStop = false;
            //
            // radMenuItem2
            //
            this.radMenuItem2.Name = "radMenuItem2";
            this.radMenuItem2.Text = "Launch Child Form 2";
            this.radMenuItem2.Click += new System.EventHandler(this.radMenuItem2_Click);
            //
            // Main
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(548, 444);
            this.Controls.Add(this.radDock1);
            this.Controls.Add(this.radMenu1);
            this.IsMdiContainer = true;
            this.Name = "Main";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Main_Load);
            ((System.ComponentModel.ISupportInitialize)(this.radMenu1)).EndInit();
            ((System.ComponentModel.ISupportInitialize)(this.radDock1)).EndInit();
            this.radDock1.ResumeLayout(false);
            ((System.ComponentModel.ISupportInitialize)(this.documentContainer1)).EndInit();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private Telerik.WinControls.UI.RadMenu radMenu1;
        private Telerik.WinControls.UI.RadMenuItem radMenuItem1;
        private Telerik.WinControls.UI.Docking.RadDock radDock1;
        private Telerik.WinControls.UI.Docking.DocumentContainer documentContainer1;
        private Telerik.WinControls.UI.RadMenuItem radMenuItem2;
    }
}

Main.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Telerik.WinControls.UI.Docking;

namespace RadControlsWinFormsApp1
{
    public partial class Main : Form
    {
        public Main()
        {
            InitializeComponent();
        }

        private void radMenuItem1_Click(object sender, EventArgs e)
        {

            ChildForm childForm = ChildForm.Instance;
            if (childForm.Parent == null)
            {
                childForm.MdiParent = this;
                childForm.Show();
            }
            else
            {
                this.radDock1.ActivateMdiChild(childForm);
            }
        }

        private void radMenuItem2_Click(object sender, EventArgs e)
        {
            ChildForm2 childForm2 = ChildForm2.Instance;
            if (childForm2.Parent == null)
            {
                childForm2.MdiParent = this;
                childForm2.Show();
            }
            else
            {
                this.radDock1.ActivateMdiChild(childForm2);
            }
        }

        private void Main_Load(object sender, EventArgs e)
        {

        }
    }
}

ChildForm.Designer.cs

namespace RadControlsWinFormsApp1
{
    partial class ChildForm
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.radLabel1 = new Telerik.WinControls.UI.RadLabel();
            ((System.ComponentModel.ISupportInitialize)(this.radLabel1)).BeginInit();
            this.SuspendLayout();
            //
            // radLabel1
            //
            this.radLabel1.Location = new System.Drawing.Point(13, 13);
            this.radLabel1.Name = "radLabel1";
            this.radLabel1.Size = new System.Drawing.Size(99, 16);
            this.radLabel1.TabIndex = 0;
            this.radLabel1.Text = "I am the child form";
            //
            // ChildForm
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(284, 262);
            this.Controls.Add(this.radLabel1);
            this.Name = "ChildForm";
            this.Text = "ChildForm";
            this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.ChildForm_FormClosed);
            ((System.ComponentModel.ISupportInitialize)(this.radLabel1)).EndInit();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private Telerik.WinControls.UI.RadLabel radLabel1;
    }
}

ChildForm.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace RadControlsWinFormsApp1
{
    public partial class ChildForm : Form
    {
        private static ChildForm instance;

        private ChildForm()
        {
            InitializeComponent();
        }

        public static ChildForm Instance
        {
            get
            {
                if (instance == null)
                {
                    instance = new ChildForm();
                }
                return instance;
            }
        }

        private void ChildForm_FormClosed(object sender, FormClosedEventArgs e)
        {
            instance.Dispose();
            instance = null;
        }

    }
}

ChildForm2.Designer.cs

namespace RadControlsWinFormsApp1
{
    partial class ChildForm2
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.radLabel1 = new Telerik.WinControls.UI.RadLabel();
            ((System.ComponentModel.ISupportInitialize)(this.radLabel1)).BeginInit();
            this.SuspendLayout();
            //
            // radLabel1
            //
            this.radLabel1.Location = new System.Drawing.Point(22, 13);
            this.radLabel1.Name = "radLabel1";
            this.radLabel1.Size = new System.Drawing.Size(96, 16);
            this.radLabel1.TabIndex = 0;
            this.radLabel1.Text = "I am Child Form 2";
            //
            // ChildForm2
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(284, 262);
            this.Controls.Add(this.radLabel1);
            this.Name = "ChildForm2";
            this.Text = "ChildForm2";
            this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.ChildForm2_FormClosed);
            ((System.ComponentModel.ISupportInitialize)(this.radLabel1)).EndInit();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private Telerik.WinControls.UI.RadLabel radLabel1;
    }
}

ChildForm2.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace RadControlsWinFormsApp1
{
    public partial class ChildForm2 : Form
    {
        private static ChildForm2 instance;

        private ChildForm2()
        {
            InitializeComponent();
        }

        public static ChildForm2 Instance
        {
            get
            {
                if (instance == null)
                {
                    instance = new ChildForm2();
                }
                return instance;
            }
        }

        private void ChildForm2_FormClosed(object sender, FormClosedEventArgs e)
        {
            instance.Dispose();
            instance = null;
        }
    }
}

Let me know if you have any questions
Richard

[meraj]

Thank You Richard,
                           Its very useful.

[Richard Slade]

You're welcome. Please remember to mark as answer.

[Emanuel Varga]

Hello Meraj, Richard

I would suggest a different approach because you do not always have the luxury to make a singleton out of a form, or in general change the structure of the form,

I believe there is an easier way of doing this, just before adding a new form you can check if that form is already part of the MdiChildren collection and just creating and adding it if it's not, like so:

using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using Telerik.WinControls.UI;
using Telerik.WinControls.UI.Docking;

public class Form1 : Form
{
    private RadDock radDock1;

    private RadMenu radMenu1;

    public Form1()
    {
        InitializeComponent();
        this.Size = new Size(800, 600);

        this.Controls.Add(radDock1 = new RadDock());
        radDock1.Dock = DockStyle.Fill;
        radDock1.MdiChildrenDockType = DockType.Document;

        this.IsMdiContainer = true;
        this.radDock1.AutoDetectMdiChildren = true;

        this.Controls.Add(radMenu1 = new RadMenu());
        radMenu1.Dock = DockStyle.Top;
        var menuItem = new RadMenuItem("Show Form1");
        menuItem.Click += new System.EventHandler(menuItem_Click);
        radMenu1.Items.Add(menuItem);
    }

    void menuItem_Click(object sender, System.EventArgs e)
    {
        var form = radDock1.MdiChildren.Where(m => m is Form2).FirstOrDefault();
        if (form == null)
        {
            form = new Form2();
            form.MdiParent = this;
            form.Visible = true;
        }
        else
        {
            radDock1.ActivateMdiChild(form);
        }
    }

    /// <summary>
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.IContainer components = null;

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

    #region Windows Form Designer generated code

    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        this.components = new System.ComponentModel.Container();
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.Text = "Form1";
    }

    #endregion Windows Form Designer generated code
}

public class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();
        this.Controls.Add(new RadLabel() { Text = "Form1" });
    }

    /// <summary>
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.IContainer components = null;

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

    #region Windows Form Designer generated code

    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        this.components = new System.ComponentModel.Container();
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.Text = "Form2";
    }

    #endregion Windows Form Designer generated code
}

This way you don't need to make your form a singleton.

Hope this helps, if you have any other questions or comments, please let me know,

Best Regards,
Emanuel Varga

Telerik WinForms MVP

[aquariens]

May be a bit late for this post but I achieved the same by comparing .text property of the form and the document by iterating the documents in dock.

Private Function IterateDockLoadForm(ByVal Form As RadForm) As Boolean

    IterateDockLoadForm = False
    Dim a = (From c As Docking.HostWindow In ucMainDock.DocumentManager.DocumentEnumerator Select c.Text)
    For i As Short = 0 To a.Count - 1
        If a(i).ToString = Form.Text Then
            IterateDockLoadForm = True
        End If
    Next

    If IterateDockLoadForm = True Then
        Return Nothing
        Exit Function
    Else
        Dim hostWindow As New Docking.HostWindow(Form)
        ucMainDock.DocumentManager.DocumentInsertOrder = Docking.DockWindowInsertOrder.ToBack
        ucMainDock.AddDocument(hostWindow)
        ucMainDock.ShowDocumentCloseButton = True
    End If

End Function

Easy calling from menus or RibbonBar

IterateDockLoadForm(FormName)

Hope it helps.

[Julian Benkov]

Hi meraj,

Thank you for sharing your solution with the community. I am sure that the others will benefit from it.

If you have feedback to share or if you have questions, feel free to write back.

All the best,
Julian Benkov
the Telerik team