Access DataGridView rows the order they were added

Question

I have a DataGridView which colors its rows when its States property is set. States is a String which represents a semicolon-separated numbers list. If I receive `"0;1;2"` the three first rows will be colored in purle, green and red respectively. The problem comes when I sort the datagrid clicking on a column header : colors are applied the same way. For example : ``` Names|Labels Name1|Label1 Name2|Label2 Name3|Label3 ``` I receive `"0;1;2"` which means `"Purple;Green;Red"` : ``` Names|Labels Name1|Label1 => Purple Name2|Label2 => Green Name3|Label3 => Red ``` I sort (descending): ``` Names|Labels Name3|Label3 => Red Name2|Label2 => Green Name1|Label1 => Purple ``` I receive `"3;4;5"` which means `"Yellow;Orange;Pink"` : ``` Names|Labels Name3|Label3 => Yellow Name2|Label2 => Orange Name1|Label1 => Pink ``` But this isn't what I was waiting for, I wanted that : ``` Names|Labels Name3|Label3 => Pink Name2|Label2 => Orange Name1|Label1 => Yellow ``` Here is my code : ``` protected Stri…

Accepted Answer

You can try using the `Tag` property of the row to place your row index number. This is how I had my DataGridView initialized:

```
dataGridView1.Rows.Add(3);
for (int i = 0; i < 3; i++) {
  dataGridView1.Rows[i].Tag = i;
  dataGridView1.Rows[i].Cells[0].Value = "Name " + i.ToString();
  dataGridView1.Rows[i].Cells[1].Value = "Label " + i.ToString();
}
```

Here is my version of your `UpdateColors` routine:

```
private void UpdateColors() {
  String[] sStates = new String[] { };
  if (m_States != null) {
    sStates = m_States.Split(';');
    for (int i = 0; i < sStates.Length;i++) {
      int nState = Convert.ToInt32(sStates[i]);
      foreach (DataGridViewRow row in dataGridView1.Rows) {
        int rowIndex = Convert.ToInt32(row.Tag);
        if (rowIndex == i) {
          row.DefaultCellStyle.BackColor = m_Couleurs_Fond_Etats[nState];
        }
      }
    }
  }
}
```

I am first looping through your splitted state string to get the row index and to convert the actual value to the color index. Then I loop through the rows to find the matching index property that I placed in the `Tag` property.

Here is a cleaned up version using just the one loop:

```
private void UpdateColors() {
  String[] sStates = new String[] { };
  if (m_States != null) {
    sStates = m_States.Split(';');
    foreach (DataGridViewRow row in dataGridView1.Rows) {
      int rowIndex = Convert.ToInt32(row.Tag);
      int colorIndex = Convert.ToInt32(sStates[rowIndex]);
      row.DefaultCellStyle.BackColor = m_Couleurs_Fond_Etats[colorIndex];
    }
  }
}
```

Needs error checking obviously.

Access DataGridView rows the order they were added

Solution

Problem