Hello.

First of all I'd like to say HI to everyone. I've recently joined this community and this is my first post.

I have a class called Numerical Calculus where the assignments often require the input and representation in a GUI of various matrices. So I've been looking for ways to do that but so far have come short. I'm working in C# now, because the GUI is easy to do but could work in C++ or Java if necessary.

What is the best way to represent in a WindowsForm a mathematical matrix? Is there a way to draw/display it directly in mathematical form (table in parentheses) or in some sort of editable/non-editable table similar to the one in Excel?

I've been looking into DataGridView but am looking for any other ideas, tips or any other kind of help. Perhaps some way of creating/generating a table of text boxes given x and y dimensions? I want to try different approaches but don't really feel like reinventing the wheel.

If there are any ways of representing a matrix/array, or perhaps some libraries that draw a picture representing said matrix, and some other way of inputting the values. Just thinking out loud.

I'd really appreciate being pointed in the right direction.

Thank you.

Hi Dragonator, welcome here at daniweb!
It just so happens I'm working on a matrix calculator project. Well not all the time of course;) And it is far from finished!
I use a class derived from DataGridView to show or edit a matrix.
I may have my the code here (as far as I know this part works):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing;

namespace MatrixCalculator
{
    class MatrixIO : DataGridView
    {
        //input output grid handler class for a matrix with doubles
        //

        #region Private fields

        private const int cDefaultSize = 3; //default row and col size

        //array for the data in the grid
        private double[,] MData;

        // Boolean flag used to determine when a character other than a number is entered.
        private bool NumberEntered = false;
        
        #endregion

        #region Constructors
        public MatrixIO()
        {
            InitializeDataGridView(cDefaultSize, cDefaultSize);
        }

        public MatrixIO(int nRows, int nCols)
        {
            InitializeDataGridView(nRows, nCols);
        }

        public MatrixIO(Point location, int nRows, int nCols)
        {
            InitializeDataGridView(nRows, nCols);
            this.Location = location;
        }
        #endregion

        #region Initialisation of the DataGridView

        private void InitializeDataGridView(int rows, int columns)
        {
            this.AllowUserToAddRows = false;
            this.AllowUserToDeleteRows = false;
            this.AllowUserToResizeRows = false;
            this.EnableHeadersVisualStyles = false;
            this.SelectionMode = DataGridViewSelectionMode.CellSelect;
            this.EditMode = DataGridViewEditMode.EditOnKeystroke;

            this.Location = new System.Drawing.Point(0, 0);
            this.Name = "dataGridView1";
            this.Size = new System.Drawing.Size(250, 125);
            this.TabIndex = 0;
            this.RowHeadersWidth = 55;
            //used to attach event-handlers to the events of the editing control(nice name!)
            this.EditingControlShowing += new DataGridViewEditingControlShowingEventHandler(this.MatrixIO_EditingControlShowing);

            this.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.DisableResizing;
            this.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.DisableResizing;

            for (int i = 0; i < columns; i++)
            {
                AddAColumn(i);
            }
            this.RowHeadersDefaultCellStyle.Padding = new Padding(3);//helps to get rid of the selection triangle?
            for (int i = 0; i < rows; i++)
            {
                AddARow(i);
            }

            this.ColumnHeadersDefaultCellStyle.Font = new Font("Verdana", 8.25F, FontStyle.Bold, GraphicsUnit.Point, ((byte)(0)));
            this.ColumnHeadersDefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;
            this.ColumnHeadersDefaultCellStyle.BackColor = Color.Gainsboro;

            this.RowHeadersDefaultCellStyle.Font = new Font("Verdana", 8.25F, FontStyle.Bold, GraphicsUnit.Point, ((byte)(0)));
            this.RowHeadersDefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;
            this.RowHeadersDefaultCellStyle.BackColor = Color.Gainsboro;

            this.ShowEditingIcon = false;
            this.SelectionMode = DataGridViewSelectionMode.CellSelect;
        }

        private void AddARow(int i)
        {
            DataGridViewRow Arow = new DataGridViewRow();
            Arow.HeaderCell.Value = "R" + i.ToString();
            this.Rows.Add(Arow);
        }

        private void AddAColumn(int i)
        {
            DataGridViewTextBoxColumn Acolumn = new DataGridViewTextBoxColumn();
            Acolumn.HeaderText = "C" + i.ToString();
            Acolumn.Name = "Column" + i.ToString();
            Acolumn.Width = 60;
            Acolumn.SortMode = DataGridViewColumnSortMode.NotSortable;
            //make a Style template to be used in the grid
            DataGridViewCell Acell = new DataGridViewTextBoxCell();
            Acell.Style.BackColor = Color.LightCyan;
            Acell.Style.SelectionBackColor = Color.FromArgb(128, 255, 255);
            Acolumn.CellTemplate = Acell;
            this.Columns.Add(Acolumn);
        }

        public void MakeMatrixTitle(string Title)
        {
            this.TopLeftHeaderCell.Value = Title;
            this.TopLeftHeaderCell.Style.BackColor = Color.AliceBlue;
        }

        #endregion

        #region Properties and property utility functions
        
        public MMatrix TheMatrix
        {
            get
            {
                MData = new double[this.RowCount, this.ColumnCount];
                ExtractTextboxes();
                return new MMatrix(MData);
            }
            set
            {
                MData = value.array;
                this.Rows.Clear();
                this.Columns.Clear();                
                InitializeDataGridView(value.Rows,value.Cols);
                FillTextboxes();
            } 
        }

        public double[,] TheData
        {
            get
            {
                MData = new double[this.RowCount, this.ColumnCount];
                ExtractTextboxes();
                return MData;
            }
            set
            {              
                int _rows = value.GetUpperBound(0) + 1;
                int _cols = value.GetUpperBound(1) + 1;
                MData = new double[_rows, _cols];
                MData = value;
                ResizeOurself(_rows, _cols);
                FillTextboxes();
            } 
        }

        private void ResizeOurself(int r, int c)
        {
            //adjust rows and cols, do nothing if they equal 
            //
            while (r < this.RowCount)
            {
                this.Rows.RemoveAt(this.RowCount - 1);
            }
            while (r > this.RowCount)
            {
                AddARow(this.RowCount);
            }
            while (c < this.ColumnCount)
            {
                this.Columns.RemoveAt(this.ColumnCount - 1);
            }
            while (c > this.ColumnCount)
            {
                AddAColumn(this.ColumnCount);
            }           
        }

        private void FillTextboxes()     //fill the textboxes
        {
            for (int r = 0; r < this.RowCount; r++)
            {
                for (int c = 0; c < this.ColumnCount; c++)
                {
                    this[c, r].Value = MData[r, c]; //notice r, c
                }
            }
        }

        private void ExtractTextboxes()
        {
            for (int r = 0; r < this.RowCount; r++)
            {
                for (int c = 0; c < this.ColumnCount; c++)
                {
                    try
                    {
                        string str = this[c, r].Value.ToString();
                        MData[r, c] = Convert.ToDouble(str.Replace('.', ','));   //notice r, c 
                    }
                    catch (Exception)
                    {
                        MData[r, c] = 0.0;  //assume for the moment this if the cell is not filled
                        //throw;
                    }
                        
                }
            }
        } 
        #endregion

        #region Key and keyboard processing
        //Check if key entered is "numeric"
        private bool CheckKey(Keys K, bool isDecimalPoint, bool isMinus)
        {
            if (K == Keys.Back) //backspace?
                return true;
            else if (K == Keys.OemPeriod || K == Keys.Decimal)  //decimal point?
                return isDecimalPoint ? false : true;       //or: return !isDecimalPoint
            else if (K == Keys.OemMinus)
                return !isMinus;
            else if ((K >= Keys.D0) && (K <= Keys.D9))      //digit from top of keyboard?
                return true;
            else if ((K >= Keys.NumPad0) && (K <= Keys.NumPad9))    //digit from keypad?
                return true;
            else
                return false;   //no "numeric" key
        }

        // Handle the KeyDown event to determine the type of character entered into the control.
        // The method here should be registered as KeyEventHandler to the EditingControl 
        // of the DataGridView in order for it to work (took me some time to figure that out...)
        private void MatrixIO_KeyDown(object sender, KeyEventArgs e)
        {
            //we know we have columns of type DataGridViewTextBoxColumn so :
            TextBox Tbx = (TextBox)sender;
            bool decimalTyped = Tbx.Text.Contains(".");
            bool minusTyped = Tbx.Text.Contains("-");
            // Initialize the flag.
            NumberEntered = CheckKey(e.KeyCode, decimalTyped, minusTyped);
        }

        // This event occurs after the KeyDown event and can be used to prevent
        // characters from entering the control.
        private void MatrixIO_KeyPress(object sender, KeyPressEventArgs e)
        {
            // Check for the flag being set in the KeyDown event.
            if (NumberEntered == false)
            {
                // Stop the character from being entered into the control since it is non-numerical.
                e.Handled = true;
            }
        }

        private void MatrixIO_KeyUp(object sender, KeyEventArgs e)
        {
            if (Control.ModifierKeys == Keys.Shift)
            {
                NumberEntered = false;
            }
        }

        private void MatrixIO_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {
            //Unsubscribe from the event in case it is subscribed

            this.EditingControl.KeyPress -= new KeyPressEventHandler(MatrixIO_KeyPress);
            this.EditingControl.KeyDown -= new KeyEventHandler(this.MatrixIO_KeyDown);

            this.EditingControl.KeyPress += new KeyPressEventHandler(MatrixIO_KeyPress);
            this.EditingControl.KeyDown += new KeyEventHandler(this.MatrixIO_KeyDown);
        }
        #endregion
    }

}
//        Here is the code you need to make the Enter key move the focus to the right:

//public class dgv : DataGridView
//{
//    protected override bool ProcessDialogKey(Keys keyData)
//    {
//        Keys key = (keyData & Keys.KeyCode);
//        if (key == Keys.Enter)
//        {
//            return this.ProcessRightKey(keyData);
//        }
//        return base.ProcessDialogKey(keyData);
//    }
//    protected override bool ProcessDataGridViewKey(KeyEventArgs e)
//    {
//        if (e.KeyCode == Keys.Enter)
//        {
//            return this.ProcessRightKey(e.KeyData);
//        }
//        return base.ProcessDataGridViewKey(e);
//    }
//}
Comments
Nice work

Thank you very much. I didn't have time to try your code for this assignment and had to simply print to a richtextbox. But for the following ones I will give it a try.

Thank you again.

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