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using c# winform 4.0

The datagridview has several columns including column ItemID
The datagridview has been populated with several rows.
Some of the rows have the same ItemID value.
I would like the rows with the same ItemID to be colour coded.

For example:
rows 2 and 5 may have the same ItemID. These two rows should have one colour
rows 6 and 7 may have the same ItemID. These two rows should have a one colour. i.e. different to the rows 2 and 5

How is this done please?

1 solution

The CellFormatting event of DataGridView can be used for this purpose as shown below:
public partial class Form1 : Form
    public Form1()
    DataGridView DataGridView1 = new DataGridView();
    Button ButtonUpdate = new Button();
    BindingSource BindingSource1 = new BindingSource();
    DataTable DataTable1 = new DataTable();
    Color[] colorTable;
    private void Form1_Load(object sender, EventArgs e)
        colorTable = new Color[]{
               Color.Blue, Color.Red, Color.Green,
               Color.Pink, Color.Plum, Color.Cyan};
        DataTable1.Columns.Add("ItemId", typeof(int), null);
        BindingSource1.DataSource = DataTable1;
        DataGridView1.DataSource = BindingSource1;

        DataGridView1.Dock = DockStyle.Fill;
        DataGridView1.CellFormatting += new DataGridViewCellFormattingEventHandler(DataGridView1_CellFormatting);


    void DataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
        if (e.ColumnIndex == 0)
                int val = (int)DataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value;
                e.CellStyle.BackColor = colorTable[val % 6];
Share this answer
arkiboys 25-Apr-12 7:56am    
I do not see how your code identifies the rows which have the same column value. Can you explain please?
VJ Reddy 25-Apr-12 8:06am    
In the CellFormatting event the contents of the First Column of the concerned is obtained as val. Then remainder of the val is calculated using val % 6. So, for any value we will get values from 0 to 5 as remainder. Here, I have used only few colors in the color table. Depending upon the range of numbers in your column, populate the color table, and find out the remainder. If the value 5 is repeated in 3 rows, we will get the same remainer for all these rows and then same color from the color table will applied as the back color in CellFormatting event.
arkiboys 25-Apr-12 8:13am    
Hi, I still do not understand this...
Because I want only to colour the rows which have the same values in say columnX.
Your code does not seem to be doing that.
Please elaborate.
VJ Reddy 25-Apr-12 8:25am    
Have you run the sample?
I have entered the values 5, 6, 7 etc. which are repeated, for which you get the same color, respectively. 5 % 6 = 5, 6 % 6 =0, 7 % 6 = 1, So, for all rows with value of 5, in the ItemId, the colorTable[5] will be applied as back color. Then for all rows with value of 6 in the ItemId, colorTable[0] will be applied as back color similarly for other values the back color is applied.
I have run the above sample and it works.
VJ Reddy 25-Apr-12 8:56am    
Hope, you understood the solution.
I will be happy if it works for you.
Thank you for your response.

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