C#: Changing Button BackColor has no effect

问题:

I'm having a problem with C# buttons in Windows Forms.

I've create a number of buttons programmatically and add them to a form afterwards.

Interestingly, every modification to those buttons (location and size) except for the modification of the BackColor is readily executed. Only the button's color remains unchanged.

The code looks something like this:

public class SimpleSortAlgDisplayer : ISortAlgDisplayer
{

    #region ISortAlgDisplayer Member

    void ISortAlgDisplayer.Init(int[] Data)
    {
        this.DataLength = Data.Length;
        this.DispWin = new CurrentSortStateWin();
        this.DispWin.Show();
        this.DispWin.Size = new Size(60 + (10 * this.DataLength), 120);

        this.myArrayElements = new Button[this.DataLength];
        for (int i = 0; i < this.DataLength; i++)
        {
            this.myArrayElements[i] = new Button();
            //begin of series of invoked actions

            this.myArrayElements[i].Size=new Size(5,(int)(((80)*(double)Data[i])/1000));
            this.myArrayElements[i].Location = new Point(30 + (i * 10), 90-(this.myArrayElements[i].Size.Height));
            this.myArrayElements[i].Enabled = true;
            this.myArrayElements[i].BackColor = Color.MidnightBlue;
            this.myArrayElements[i].UseVisualStyleBackColor = true;
            this.DispWin.Controls.Add(this.myArrayElements[i]);
            this.myArrayElements[i].Refresh();

        }
    }

Ideas anyone?

A similar question was asked here but the answers to it were not very helpful:

• Trying to use Invoke gives me the run-time error that DispWin is not yet created.
• Setting UseVisualStyleBackColor to false changes nothing.
• Setting BackColor and ForeColor or Showing DispWin only after adding and formatting the Buttons also had no effect.

Where am I going wrong?

回答1:

You are trying to set up the color, but then you override it saying UseVisualStyleBackColor = true

if you want to use your custom color, you need to set UseVisualStyleBackColor to false or the color will only be applied to the button upon mouse over.

a simple test uploaded to GitHub

public partial class mainForm : Form
{
    Random randonGen = new Random();

    public mainForm()
    {
        InitializeComponent();
    }

    private void mainForm_Load(object sender, EventArgs e)
    {
        populate();
    }

    private void populate()
    {
        Control[] buttonsLeft = createButtons().ToArray();
        Control[] buttonsRight = createButtons().ToArray();

        pRight.Controls.AddRange(buttonsRight);
        pLeft.Controls.AddRange(buttonsLeft);
    }

    private List<Button> createButtons()
    {
        List<Button> buttons = new List<Button>();

        for (int i = 1; i <= 5; i++)
        {

            buttons.Add(
                new Button()
                {
                    Size = new Size(200, 35),
                    Enabled = true,
                    BackColor = GetColor(),
                    ForeColor = GetColor(),
                    UseVisualStyleBackColor = false,
                    Left = 20,
                    Top = (i * 40),
                    Text = String.Concat("Button ", i)
                });
        }

        return buttons;
    }

    private Color GetColor()
    {
        return Color.FromArgb(randonGen.Next(255), randonGen.Next(255), randonGen.Next(255));
    }
}

result

回答2:

If FlatStyle for button is set to System, it will not show any backcolor rather use backcolor from template of system colors.

回答3:

Make sure you do not have a BackgroundImage set. This overrides the BackColor.