reference checkbox by name

Question

How to reference checkbox by name (string), in C# Windows Forms? I am trying

CheckBox cb = (CheckBox)Controls["checkBox" + id];
if (cb.Checked)
{
    MessageBox.Show(id);
}

I am getting

Error   2   Cannot convert type 'System.Windows.Forms.Control' to 'Vts_SI.CheckBox' C:\Users\Administrator\Documents\Visual Studio 2010\Projects\My2\My2\GlavniProzor.cs    67  27  Vts_SI
Error   3   'Vts_SI.CheckBox' does not contain a definition for 'Checked' and no extension method 'Checked' accepting a first argument of type 'Vts_SI.CheckBox' could be found (are you missing a using directive or an assembly reference?)   C:\Users\Administrator\Documents\Visual Studio 2010\Projects\My2\My2\GlavniProzor.cs    68  20  Vts_SI

Provide the exact error you get. and also is this compile time error or runtime Exception ? — Sriram Sakthivel
– Sriram Sakthivel, Commented Jan 18, 2014 at 17:33
Error occurs in design time. Updated full error list response. — Slinava Surla
– Slinava Surla, Commented Jan 18, 2014 at 17:42
The actual problem is that there is no .Checked function available for that control, you should take a look at the documentation. — Max
– Max, Commented Jan 18, 2014 at 17:45
I have edited your title. Please see, "Should questions include “tags” in their titles?", where the consensus is "no, they should not". — John Saunders
– John Saunders, Commented Jan 18, 2014 at 17:50

BartoszKP · Accepted Answer · 2014-01-18 20:29:49Z

4

You may have a class with the some name CheckBox you should specify explicitly the name space

System.Windows.Forms.CheckBox cb
    = (System.Windows.Forms.CheckBox)Controls["checkBox" + id];

edited Jan 18, 2014 at 20:29

BartoszKP

36k15 gold badges109 silver badges135 bronze badges

answered Jan 18, 2014 at 17:38

BRAHIM Kamel

13.8k1 gold badge38 silver badges47 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Sriram Sakthivel Over a year ago

+1 and finally we got the winner, I was waiting for OP to confirm this is a compile time error.

Sriram Sakthivel Over a year ago

Typing variable is not enough I suppose, you may need the same in cast also:)

Slinava Surla Over a year ago

This still gives Error 2 Cannot convert type 'System.Windows.Forms.Control' to 'Vts_SI.CheckBox' - What am I missing?

BRAHIM Kamel Over a year ago

@SlinavaSurla take a look I updated my answer what is missing is the namespace even in the cast

Community · Accepted Answer · 2017-05-23 12:29:17Z

1

Use this:

public T Control<T>(String id) where T : Control
{
   foreach (Control ctrl in MainForm.Controls.Find(id, true))
   {
      return (T)ctrl; // Form Controls have unique names, so no more iterations needed
   }
   throw new Exception("Control not found!");
}

edited May 23, 2017 at 12:29

CommunityBot

11 silver badge

answered Jan 18, 2014 at 17:31

user1968030

1 Comment

BartoszKP Over a year ago

This doesn't make any sense. For example, why use foreach to do at most one iteration?

user3210324 · Accepted Answer · 2014-01-18 18:05:55Z

0

Controls.Add(dynamicCheckBox);

Why don't you try Dynamic checkbox instead.

system.Windows.Forms.dynamiccheckBox cb1 = (dynamiccheckBox)Controls["dynamiccheckBox" + id];

answered Jan 18, 2014 at 18:05

user3210324

262 bronze badges

Comments

Max · Accepted Answer · 2014-01-18 17:40:17Z

Type: System.Windows.Forms.CheckState One of the CheckState enumeration values. The default value is Unchecked. Try this but a bit lengthy

using System;
using System.Windows.Forms;

namespace DynamicCheckBoxes
{
    static class Program
    {
        [STAThread]
        static void Main()
        {
            // Create example Form (normally you would create it with the VS Forms Designer)
            Form form = new Form();

        // Use a Panel to add the CheckBoxes during runtime
        Panel panel = new Panel();
        panel.Dock = DockStyle.Fill;
        panel.Parent = form;

        // Add a button to the form for creating the CheckBoxes during runtime
        Button button = new Button();
        button.Text = "Add a new CheckBox";
        button.Dock = DockStyle.Bottom;
        button.Parent = form;

        // On Button.Click we add a new CheckBox - we use a inline delegate here
        // Remark: Notice how the "outer" scope variables are captured.
        int iCount = 0;
        button.Click += delegate(object sender, EventArgs e)
        {
            iCount++;
            CreateCheckbox("cbDynamic" + iCount, "Dynamic" + iCount, panel, SampleCheckChangedHandler);
        }; 

        // Now let's create some Checkboxes in code 
        // I created a helper function to do the job.
        CreateCheckbox("cbActs", "Acts", panel, SampleCheckChangedHandler);
        CreateCheckbox("cbLaw", "Law", panel, SampleCheckChangedHandler);
        CreateCheckbox("cbHouses", "Houses", panel, SampleCheckChangedHandler);
        CreateCheckbox("cbCar", "Car", panel, SampleCheckChangedHandler);           

        Application.Run(form);
    }

    /// <summary>
    /// Helper function to create a CheckBox with common properties and adding it to the given parent control.
    /// </summary>
    /// <param name="Name"> Name for the new CheckBox </param>
    /// <param name="Text"> Text of the new CheckBox </param>
    /// <param name="ctrlParent"> Parent control for the new CheckBox (can be null if parent is set through other logic later) </param>
    /// <param name="handlerCheckChanged"> Handler for the CheckChanged event (can be null if no handler is needed) </param>
    /// <returns> The new Checkbox </returns>
    static CheckBox CreateCheckbox(string strName, string strText, Control ctrlParent, EventHandler handlerCheckChanged)
    {
        CheckBox cb = new CheckBox();
        cb.Name = strName;
        cb.Text = strText;
        cb.Dock = DockStyle.Top; // give a thought on how to do the dynamic layout,
        // maybe use a container control..
        cb.Parent = ctrlParent; // same as ctrlParent.Controls.Add(cb)
        // add some EventHandler (use this code as template if other handlers are commonly needded,
        // but add/set handlers/properties for specific CheckBoxes created with this function to the 
        // returned CheckBox object
        cb.CheckedChanged += handlerCheckChanged;

        return cb;
    }

    /// <summary>
    /// Sample eventhandler for the CheckChanged event
    /// </summary>
    static void SampleCheckChangedHandler(object objSender, EventArgs ea)
    {
        CheckBox cb = objSender as CheckBox; // get a reference to the checked/unchecked CheckBox

        // Do something just for demo
        if (cb.Checked)
            MessageBox.Show(cb.Text + " checked");
        else
            MessageBox.Show(cb.Text + " unchecked");
    }
}

}

Collectives™ on Stack Overflow

reference checkbox by name

4 Answers 4

4 Comments

1 Comment

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

4 Comments

1 Comment

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related