How do I use winforms to display a dropdown box only when a certain variable is true?

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I currently have a dropdown box called, "dropdownDeviceSelector" with the current fields in the Main.Designer.cs class:

this.dropdownDeviceSelector.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)| System.Windows.Forms.AnchorStyles.Right))); 
this.dropdownDeviceSelector.FormattingEnabled = true;
this.dropdownDeviceSelector.Location = new System.Drawing.Point(407, 100);
this.dropdownDeviceSelector.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
this.dropdownDeviceSelector.Name = "dropdownDeviceSelector";
this.dropdownDeviceSelector.Size = new System.Drawing.Size(100, 28);
this.dropdownDeviceSelector.TabIndex = 4;

And then, I have a function in my Main.cs file called, "chooseDevice":

private void chooseDevice(object sender, EventArgs e)
        {
            // display the dropdown menu when this function is called
        }

However, I only want the dropdownDeviceSelector to appear when the function chooseDevice is called. I'm very new to winforms so I don't really know how to implement this.

What I have tried:

I have tried calling the dropdown box in the function to no avail. I'm very new to winforms so I'm not really sure how this is done.

Posted 9-Dec-20 3:21am

stevenlam505

Updated 9-Dec-20 3:51am

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CHill60 9-Dec-20 9:46am

What is the actual control - is it a ComboBox?

stevenlam505 9-Dec-20 9:47am

Yes it is using ComboBox

CHill60 9-Dec-20 9:51am

Is there a .Visible property - if you type this.dropdownDeviceSelector then a full stop you should get a list of properties and methods. Look for Visible - if it is there then just set it to False to make the control disappear and True to bring it back

stevenlam505 9-Dec-20 9:58am

Ah, this worked, thank you!

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Richard MacCutchan · Accepted Answer · 2020-12-09T03:51:00

Solution 1

You could make the dropdown box non-visible so it only shows when you call your function. But it does rather depend on what exactly you are trying to achieve. What is contained in the device list, and how does the user cause the chooseDevice function to be called? In most cases you would have the list showing, and have some action button which is disabled, but gets enabled when the user makes a selection from the dropdown.

Posted 9-Dec-20 3:51am

Richard MacCutchan

Comments

stevenlam505 9-Dec-20 9:55am

The device list will only contain two choices, and when they select a choice, I want that choice to be stored inside of a variable named deviceChoice. In most cases, I want the list to be not visible unless the user chooses an option in another menu. IE, if the user chooses to "Choose Device" instead of "Modify Device", it displays the dropdown menu.

Richard MacCutchan 9-Dec-20 10:27am

OK, so once the user selects "Choose Device" you can show the dropdown. You can either do it by changing the Visible property, or creating the dropdown dynamically at run time. The second option may be the better choice, assuming this is the only time you require the dropdown. It does seem something of overkill to use a dropdown list when there are only two choices. You could get just the same effect with a pair of radio buttons.