Question

I have a grid of labels. In order to access them in a programmatically sensible manner, I changed them from:

gridLabel1
gridLabel2
...
gridLabelN

To:

gridLabel[0]
gridLabel[1]
...
gridLabel[N-1]

But now the designer is complaining that

The variable ‘gridLabel’ is either undeclared or was never assigned.

Despite the fact that I also changed this:

private System.Windows.Forms.Label gridLabel1 = new System.Windows.Forms.Label;
private System.Windows.Forms.Label gridLabel2 = new System.Windows.Forms.Label;
...
private System.Windows.Forms.Label gridLabelN = new System.Windows.Forms.Label;

To:

private System.Windows.Forms.Label[] gridLabel = new System.Windows.Forms.Label[N];

What have I missed?

Answer 1

Don’t mess around with generated code yourself. The designer.cs file is supposed to be managed by the forms-designer itself, not by the user. In particular, it’s easy to test that the designer does not tolerate the procedure you appear to be following:

1. Declaring a field of an array of controls to the designer file.
2. Using this field to populate the form’s control-collection by modifying the generated InitializeComponent method.

When I do so, I get the same error that you do.

The usual solution for this sort of requirement is to use a programmatic technique to add a number of controls to a parent-control’s control-collection. Ideally, create your own user-control that can hold a number of Labels (which it populates programmatically). Then, you can use this control on your form with full designer support.

EDIT:

For example (sketch only, without the user-control), add a FlowLayoutPanel to the form via the designer.

Then change the form’s constructor to:

public MyForm()
{
    InitializeComponent();

    var labels = Enumerable.Range(0, 100)
                           .Select(i => new Label { Text = i.ToString() })
                           .ToArray();

    flowLayoutPanel1.Controls.AddRange(labels);
}

Obviously, such a solution may not be appropriate if you don’t want the labels organized in a flow-layout.