How can I color rows in datagridview with condition C#

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Hello,

I want with a condition : * all rows have bool_badge =0 : color with RED * all rows have bool_badge=1 : color with ForestGreen

I have a code Correct BUT just when i click for a cell specific:

But i have result just when i click in a specific ROW

But I want when i execute my application , the test begin if bool_badge 0 or 1, and i have for all the gridview : color RED or ForestGreen ,

I try this code:

But i have ERROR!

in this ligne :

C#

string valeur = dataGridView1[2, i].Value.ToString();

The NullReferenceException was unhandled

Object reference not set to an instance of an object

How can i fix it?

Very thanks,

What I have tried:

* Code for just a specific ROW:

C#

foreach (DataGridViewRow dr in dataGridView1.Rows)
           {
               int row = this.dataGridView1.CurrentCell.RowIndex;
               string valeur = dataGridView1[2, row].Value.ToString();

               if (valeur == "0")
               {
                   dataGridView1.DefaultCellStyle.SelectionBackColor = Color.Red;
               }
               else
               {
                   dataGridView1.DefaultCellStyle.SelectionBackColor = Color.ForestGreen;
               }
           }

* My try code:

C#

for (int i = 0; i < dataGridView1.Rows.Count; i++)
        {                
            string valeur = dataGridView1[2, i].Value.ToString();

            if (valeur == "0")
            {
                dataGridView1.DefaultCellStyle.SelectionBackColor = Color.Red;
            }
            else
            {
                dataGridView1.DefaultCellStyle.SelectionBackColor = Color.ForestGreen;

Posted 2-Nov-16 1:17am

ThabetMicrosoft

Updated 2-Nov-16 4:49am

v3

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2 solutions

Solution 1

Handle the DataGridView.RowPrePaint Event (System.Windows.Forms)[^] and do it in there. The DataGridViewRowPrePaintEventArgs parameter contains the RowIndex which lets you decide what colour to paint the background.

Posted 2-Nov-16 1:37am

OriginalGriff

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ThabetMicrosoft · Accepted Answer · 2016-11-02T04:49:00

I find the Coreect code,

with use Datagridview Cell_Formatting event

C#

private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
        {
            if (dataGridView1.Columns[e.ColumnIndex].HeaderText == "bool_badge" && dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value != null) 
         // if the column is bool_badge and check null value for the extra row at dgv
            {
                    if (dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString() == "0")
                    {
                        dataGridView1.Rows[e.RowIndex].DefaultCellStyle.BackColor = Color.Red;
                    }
                    if (dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString() == "1")
                    {
                        dataGridView1.Rows[e.RowIndex].DefaultCellStyle.BackColor = Color.ForestGreen;
                    }
            }
        }