NickV987 NickV987 - 3 months ago 24
C# Question

Center a Panel within a Panel, which is in a TableLayoutPanel, in C#

So basically I've got a game board going, represented by a TableLayoutPanel. Each cell of the TableLayoutPanel represents a space on the board and contains a Panel. Each Panel has a Label in it to display what is currently in that space (e.g. a character or building) and its BackColor represents what kind of terrain that space is (e.g. Land, Water, etc.). When the player attempts to move a character, each possible space that that character can move will become "highlighted." The player will then double click one of the highlighted spaces to move the character there.

In order to highlight a space, I add a Panel to the existing Panel (the one that already has a Label in it).

So to recap, TableLayoutPanel --> Panel --> Label, Panel.

The main problem I'm having is that I can't get the "highlight-Panel" to center within its parent Panel; it's always Top-Left Centered. I want to be able to see part of the BackColor of the parent Panel in order to make it easier for the player to decide where to go. Thus, setting Dock to Fill is not an option. The highlight-Panel is slightly smaller than the parent Panel, thereby allowing for the edges of the parent Panel's BackColor to be visible. Yes, Anchor is set to None.

The secondary problem is that I cannot get any of the Labels' text colors to change. I've tried changing it at initialization or more directly with a specific location using "tableLayoutPanel.GetControlFromPosition(16, 4).Controls[0].ForeColor = Color.White;" but nothing seems to work.

To be honest, I'm not interested in super complicated hack fixes. But if there's something simple or something I missed, I'd really appreciate some input. Thanks.

This is the code that creates the TableLayoutPanel, the Panels within that, and the Labels within each Panel:

// Create TableLayoutPanel to hold Panels
tableLayoutPanel = new TableLayoutPanel()
{
RowCount = 1,
ColumnCount = 1,
AutoSize = true,
AutoSizeMode = AutoSizeMode.GrowAndShrink,
Location = new Point(12, 12),
Dock = DockStyle.Fill,
AutoScroll = true,
};

// Add tableLayoutPanel to the form
this.Controls.Add(tableLayoutPanel);

// Reset and add rows/columns + styles
tableLayoutPanel.RowStyles.Clear();
tableLayoutPanel.ColumnStyles.Clear();

for (int i = 0; i < rows; i++)
{
tableLayoutPanel.RowCount++;
tableLayoutPanel.RowStyles.Add(new RowStyle(SizeType.Percent, 50F));
}
tableLayoutPanel.RowCount--;

for (int j = 0; j < cols; j++)
{
tableLayoutPanel.ColumnCount++;
tableLayoutPanel.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50F));
}
tableLayoutPanel.ColumnCount--;

// Add Panels to TableLayoutPanel
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < cols; j++)
{
// Create new Panel
Panel space = new Panel()
{
BackColor = SystemColors.ActiveCaption,
BorderStyle = BorderStyle.FixedSingle,
Margin = new Padding(0),
Size = new Size(45, 45)
};

space.MouseClick += new MouseEventHandler(clickOnSpace);

// Create new Label
Label info = new Label()
{
Size = new Size(93, 93),
Text = "Info",
Dock = DockStyle.Fill,
TextAlign = ContentAlignment.MiddleCenter,
Enabled = false,
Font = new Font("Microsoft Sans Serif", 6),
ForeColor = Color.White
};

// Add Label to Panel
space.Controls.Add(info);

// Add Panel to TableLayoutPanel
tableLayoutPanel.Controls.Add(space, j, i);
}
}


And the code that creates the highlight-Panel:

// Highlight potential positions using possibleMoves
private void Highlight(List<Tuple<int, int>> possibleMoves, int remaining)
{
int r = 0;
int c = 0;

foreach (Tuple<int, int> pair in possibleMoves)
{
r = pair.Item1;
c = pair.Item2;

// If highlight-Panel doesn't already exist
if (tableLayoutPanel.GetControlFromPosition(c, r).Controls.Count == 1)
{
// Create a Panel to highlight the space
Panel highlight = new Panel()
{
Name = "highlight",
Size = new Size(30, 30),
BackColor = Color.Yellow,
Anchor = AnchorStyles.None
};

highlight.MouseDoubleClick += new MouseEventHandler(doubleClickOnSpace);

// Add highlight Panel to space Panel
tableLayoutPanel.GetControlFromPosition(c, r).Controls.Add(highlight);
// Bring highlight Panel to front
tableLayoutPanel.GetControlFromPosition(c, r).Controls[1].BringToFront();
}
}
}

Answer

So I actually reached a less complicated method. Instead of having a Panel within a Panel, I opted for keeping my original Panel, and creating a custom Label, which has an outside border whose thickness and color can be changed. This way I don't have to keep track of too many controls, and the CustomLabel displays everything needed.

Code for CustomLabel:

public class CustomLabel : Label
{
// Constructors

    // Default Constructor
    public CustomLabel() : base() { }

    public CustomLabel(bool drawBorder, int borderThickness, Color borderColor, Color textColor) : base()
    {
        if (drawBorder)
        {
            BorderThickness = borderThickness;
            BorderColor = borderColor;
        }

        Size = new Size(36, 36);
        Text = "Info";
        Anchor = (AnchorStyles.Left | AnchorStyles.Right);
        AutoSize = false;
        TextAlign = ContentAlignment.MiddleCenter;
        Enabled = false;
        Font = new Font("Microsoft Sans Serif", 6);
        ForeColor = TextColor;
        BorderStyle = BorderStyle.FixedSingle;
        Dock = DockStyle.Fill;

    }

    // Creates a border of specified thickness and color
    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);

        if (BorderStyle == BorderStyle.FixedSingle)
        {
            int halfThickness = BorderThickness / 2;
            using (Pen p = new Pen(BorderColor, BorderThickness))
            {
                e.Graphics.DrawRectangle(p, new Rectangle(halfThickness,
                     halfThickness,
                     ClientSize.Width - BorderThickness, ClientSize.Height - BorderThickness));
            }
        }
    }

    public int BorderThickness { get; set; }
    public Color BorderColor { get; set; }
}

Code for adding CustomLabel to Panels:

// Add Panels to TableLayoutPanel
for (int i = 0; i < rows; i++)
{
    for (int j = 0; j < cols; j++)
    {
        // Create new Panel
        Panel space = new Panel()
        {
            Size = new Size(45, 45),
            Dock = DockStyle.Fill,
            Margin = new Padding(0),
            ForeColor = Color.Red
        };

        space.MouseClick += new MouseEventHandler(MouseDownOnSpace);

        CustomLabel info = new CustomLabel(false, 0, Color.Empty, Color.Red);  // Create new CustomLabel
        space.Controls.Add(info);   // Add CustomLabel to Panel
        tlp.Controls.Add(space, j, i);      // Add Panel to TableLayoutPanel
    }
}

Code for adjusting the CustomLabel:

((CustomLabel)tlp.GetControlFromPosition(col, row).Controls[0]).BorderThickness = 6;

((CustomLabel)tlp.GetControlFromPosition(col, row).Controls[0]).BorderColor = Color.Yellow;

tlp.GetControlFromPosition(col, row).Controls[0].Text = tlp.GetControlFromPosition(col, row).Controls[0].Text;  // Transfer space information

tlp.GetControlFromPosition(col, row).Refresh();     // Refresh Panel to show changes

This is the end result:

enter image description here