Show Hide Image in DataGridView Cell

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Introduction

This post is regarding how to show and hide Image within the DataGridViewCells. The user can also opt to view the image within the available display area.

The following routine helps to show the image in the cell. The Image in the cell is saved as bytearray which is converted back to image, then replaces the DataGridViewTextboxCell with an DataGridViewImageCell where the image cell is loaded with the image.

/// <summary>
/// Routine Perform ShowPicture for the
/// selected cell in the provided GridControl
/// </summary>
/// <param name="myGrid"></param>
/// <param name="dgvCell"></param>
/// <param name="fillIn"></param>
private void ShowPicture(DataGridView myGrid, DataGridViewCell dgvCell, bool fillIn)
{
    if (!_myAttachments.ContainsKey(dgvCell.RowIndex) || 
		_myAttachments[dgvCell.RowIndex] == null)
        return;

    //get the image
    byte[] byteData = _myAttachments[dgvCell.RowIndex];
    Image returnImage = null;

    //I was not able to figure out a way to check the format of bytearray, instead     
    //I'm using a try-catch statement which will throw an exception if not an image
    try
    {
        //Convert byte to Image
        MemoryStream ms = new MemoryStream(byteData);
        returnImage = Image.FromStream(ms, false, true);
    }
    catch
    {
        MessageBox.Show("Not an Image File", "Show Picture", 
		MessageBoxButtons.OK, MessageBoxIcon.Warning);
        return;
    }

    //Initialize new DataGridViewImageCell for the image to load
    DataGridViewImageCell dgImageCol = new DataGridViewImageCell();

    //Resize the Image
    if (fillIn)
        returnImage =ResizeImageToFitInsideTheGrid(returnImage, myGrid);

    dgImageCol.Value = returnImage;

    //When ImageWidth is greater than ColumnWidth
    //Increase the width of the column to show full size of the image
    if (myGrid.Columns[dgvCell.ColumnIndex].Width < returnImage.Width)
        myGrid.Columns[dgvCell.ColumnIndex].Width = returnImage.Width;

    //Increase the height of the column to show full size of the image   
    if (myGrid.Rows[dgvCell.RowIndex].Height < returnImage.Height)
        myGrid.Rows[dgvCell.RowIndex].Height = returnImage.Height;

    //Assign the DataGridViewImageCell to the Selected Cell
    myGrid[dgvCell.ColumnIndex, dgvCell.RowIndex] = dgImageCol;
}

Hide the Picture routine, replace the DataGridViewImageCell with a DataGridViewTextboxCell and load the file name in it.

private void HidePicture(DataGridView myGrid, DataGridViewCell dgvCell)
{
    Type tp = dgvCell.GetType();
    //Check the cell type of DatabaseStorage Field is "DataGridViewTextBoxCell"
    if (tp.Name == "DataGridViewImageCell")
    {
        //Initialize new DataGridViewTextBoxCell for the text to load
        DataGridViewTextBoxCell dgTxtCol = new DataGridViewTextBoxCell();
        //Assign the file name to the cell
        dgTxtCol.Value = _myAttachmentFileNames[dgvCell.RowIndex];

        //Assign the DataGridViewTextBoxCell to the Cell of DatabaseStorage Field 
        myGrid[dgvCell.ColumnIndex, dgvCell.RowIndex] = dgTxtCol;
        myGrid.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.AllCells;
    }
}

Resizing the Image

1. Image with large Width & Height
2. Image with large Width
3. Image with large Height
4. Image with small Width

private Image ResizeImageToFitInsideTheGrid(Image returnImage, DataGridView myGrid)
{
    //Case 1: Image with Large Width & Height - 
    //      Reduce image height to display height & proportionate width
    //      if the proportionate width is still greater than the display width
    //      Reduce image width to display width & proportionate height
    //Case 2: Image with Large Width - 
    //      Reduce image width to display Width & proportionate Height
    //Case 3: Image with Large Height - 
    //      Reduce image height to display Height + proportionate Width
    //Case 4: Image with Small Width & Height - Do Nothing

    //Multiplying by 0.95 helps the image to fit inside the display area

    int dgvDisplayHeight = Convert.ToInt32
	((myGrid.DisplayRectangle.Height - myGrid.ColumnHeadersHeight) * .95);
    int dgvDisplayWidth = Convert.ToInt32
	((myGrid.DisplayRectangle.Width - myGrid.RowHeadersWidth) * .95);

    //Large Width & Large Height 
    if (returnImage.Width >= dgvDisplayWidth && returnImage.Height >= dgvDisplayHeight)
    {
        int h = Convert.ToInt32(dgvDisplayHeight);
        int w = Convert.ToInt32(h * (Convert.ToDouble(returnImage.Width) / 
			Convert.ToDouble(returnImage.Height)));
        //if the proportionate width is still greater than the display width
        if (w > dgvDisplayWidth)
        {
            w = Convert.ToInt32(dgvDisplayWidth);
            h = Convert.ToInt32(w * (Convert.ToDouble(returnImage.Height) / 
			Convert.ToDouble(returnImage.Width)));
        }
        returnImage = ResizeImage(returnImage, w, h);
    }
    //Large Height 
    else if (returnImage.Width <= dgvDisplayWidth && returnImage.Height >= 
			dgvDisplayHeight)
    {
        int h = Convert.ToInt32(dgvDisplayHeight);
        int w = Convert.ToInt32(h * (Convert.ToDouble(returnImage.Width) / 
			Convert.ToDouble(returnImage.Height)));
        returnImage = ResizeImage(returnImage, w, h);
    }
    //Large Width
    else if (returnImage.Width >= dgvDisplayWidth && 
		returnImage.Height <= dgvDisplayHeight)
    {
        int w = Convert.ToInt32(dgvDisplayWidth);
        int h = Convert.ToInt32(w * 
	(Convert.ToDouble(returnImage.Height) / Convert.ToDouble(returnImage.Width)));
        returnImage = ResizeImage(returnImage, w, h);
    }
    return returnImage;
}

/// <summary>
/// Routine will resize the given images with
/// the provided height and width
/// </summary>
/// <param name="actualImage">Original Image</param>
/// <param name="width">new width</param>
/// <param name="height">new height</param>
/// <returns>Resized Image</returns>
private Image ResizeImage(Image actualImage, int width, int height)
{
    Bitmap bitmap = new Bitmap(width, height);
    using (Graphics graphics = Graphics.FromImage((Image)bitmap))
        graphics.DrawImage(actualImage, 0, 0, width, height);

    return (Image)bitmap;
}