How to make TableLayoutPanel with resizable cells like using Splitter

Question

Got TableLayoutPanel with 1 column and N rows needed to cells be resizable with somthing like Splitter component between cells. without using SplitContainer.

May be any other idea without TableLayoutPanel?

Answer 1

It really depends on what you want to do with it: A DataGridView brings with it the interactivity, but its cells are neither controls nor containers..

You can try if this TableLayoutPanel subclass does what you want:

public partial class SplitTablePanel : TableLayoutPanel
{
    public int SplitterSize { get; set; }

    int sizingRow = -1;
    int currentRow = -1;
    Point mdown = Point.Empty;
    int oldHeight = -1;
    bool isNormal = false;
    List<RectangleF> TlpRows = new List<RectangleF>();
    int[] rowHeights = new int[0];

    public SplitTablePanel()
    {
        InitializeComponent();
        this.MouseDown += SplitTablePanel_MouseDown;
        this.MouseMove += SplitTablePanel_MouseMove;
        this.MouseUp += SplitTablePanel_MouseUp;
        this.MouseLeave += SplitTablePanel_MouseLeave;
        SplitterSize = 6;
    }

    void SplitTablePanel_MouseLeave(object sender, EventArgs e)
    {
        Cursor = Cursors.Default;
    }


    void SplitTablePanel_MouseUp(object sender, MouseEventArgs e)
    {
        getRowRectangles(SplitterSize);
    }

    void SplitTablePanel_MouseMove(object sender, MouseEventArgs e)
    {
        if (!isNormal) nomalizeRowStyles();
        if (TlpRows.Count <= 0) getRowRectangles(SplitterSize);
        if (rowHeights.Length <= 0) rowHeights = GetRowHeights();

        if (e.Button == System.Windows.Forms.MouseButtons.Left)
        {
            if (sizingRow < 0) return;
            int newHeight = oldHeight + e.Y - mdown.Y;
            sizeRow(sizingRow, newHeight);
        }
        else
        {
            currentRow = -1;
            for (int i = 0; i < TlpRows.Count; i++)
                if (TlpRows[i].Contains(e.Location)) { currentRow = i; break;}
            Cursor = currentRow >= 0 ? Cursors.SizeNS : Cursors.Default;
        }
    }

    void SplitTablePanel_MouseDown(object sender, MouseEventArgs e)
    {
        mdown = Point.Empty;
        sizingRow = -1;
        if (currentRow < 0) return;
        sizingRow = currentRow;
        oldHeight = rowHeights[sizingRow];
        mdown = e.Location;
    }


    void getRowRectangles(float size)
    {   // get a list of mouse sensitive rectangles
        float sz = size / 2f;
        float y = 0f;
        int w = ClientSize.Width;
        int[] rw = GetRowHeights();

        TlpRows.Clear();
        for (int i = 0; i < rw.Length - 1; i++)
        {
            y += rw[i];
            TlpRows.Add(new RectangleF(0, y - sz, w, size));
        }

    }

    void sizeRow(int row, int newHeight)
    {   // change the height of one row
        if (newHeight == 0) return;
        if (sizingRow < 0) return;
        SuspendLayout();
        rowHeights = GetRowHeights();
        if (sizingRow >= rowHeights.Length) return;

        if (newHeight > 0) 
            RowStyles[sizingRow] = new RowStyle(SizeType.Absolute, newHeight);
        ResumeLayout();
        rowHeights = GetRowHeights();
        getRowRectangles(SplitterSize);
    }

    void nomalizeRowStyles()
    {   // set all rows to absolute and the last one to percent=100!
        if (rowHeights.Length <= 0) return;
        rowHeights = GetRowHeights();
        RowStyles.Clear();
        for (int i = 0; i < RowCount - 1; i++)
        {
            RowStyle cs = new RowStyle(SizeType.Absolute, rowHeights[i]);
            RowStyles.Add(cs);
        }
        RowStyles.Add ( new RowStyle(SizeType.Percent, 100) );
        isNormal = true;
    }
}
}