如何给字典添加标签 Windows Forms App

Question

counter=1;
while (counter < 100)
{
    label = "label" + counter;
    buttoncontrol.Add(counter, label);
    buttoncontrol[counter].BackColor=Color.Brown;
    counter++;
}

I am trying to add labels to a dictionary so I can call them up later in the program. The code shown results in the error Cannot convert from string to systems.windows.forms.label. I am hoping to save each label with there respected number eg: 1, label1 2, label2 3, label 3

Answer 1

Your question is how to add Labels to a Dictionary in a WinForms app.

Here's an example of one way to add 100 labels to a dictionary, that at the same time will place them in a FlowLayoutPanel to provide a basis for a simple test.

private void addLabelsToDictionary()
{
    for (int i = 1; i <= 100; i++)
    {
        var label = new Label
        {
            Name = $"label{i}",
            Text = $"{i}",
            TextAlign = ContentAlignment.MiddleCenter,
            BackColor = Color.Brown,
            ForeColor= Color.White,
            Size = new Size(45, 45),
            Margin = new Padding(5),
        };
        buttonControl[i] = label;
    }
}
private readonly Dictionary<int, Label> buttonControl = new Dictionary<int, Label>();

This method can be called in the main form constructor.

public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();
        flowLayoutPanel.MaximumSize = new Size(1100, int.MaxValue);
        flowLayoutPanel.AutoSize= true;
        addLabelsToDictionary();
        // Populate flow layout panel
        foreach (var label in buttonControl.Values)
        {
            flowLayoutPanel.Controls.Add(label);
        }
        textBoxSearch.TextChanged += onSearch;
    }

---

It sounds like you want labels to "come and go" during the applications's runtime. A basic test for this functionality uses a text box for comma-delimited values corresponding to the dictionary keys.

    private void onSearch(object? sender, EventArgs e)
    {
        // Changing 'Visible' works but is SLOW for ~100 labels.
        // Do this instead:
        flowLayoutPanel.Controls.Clear();
        if (string.IsNullOrEmpty(textBoxSearch.Text))
        {
            foreach (var label in buttonControl.Values)
            {
                flowLayoutPanel.Controls.Add(label);
            }
        }
        else
        {
            var parse = textBoxSearch.Text.Split(',');
            foreach (var sVal in parse)
            {
                if (int.TryParse(sVal, out int value) &&
                    buttonControl.TryGetValue(value, out Label label))
                {
                    flowLayoutPanel.Controls.Add(buttonControl[value]);
                }
            }
        }
    }
}