c# - How to find a string in DataGridView from TextBox?

Question

hi i am new to Linq Queries, And this code is copied from internet

     object cells = from r in dataGridView1.Rows.Cast<DataGridViewRow>()where !r.IsNewRowArray.ConvertAll<DataGridViewCell, string>(r.Cells.Cast<DataGridViewCell>().ToArray, dgvc => dgvc.Value.ToString)where c.Contains(textBox1.Text)
                             select new  cell {
                            rowIndex = r.Index, 
                           columnIndex = Array.IndexOf(c, _textBox1.Text)};

and by using the following code i am fiding the string in a datagridview cell.

 object cells = from r in dataGridView1.Rows.Cast<DataGridViewRow>()where !r.IsNewRowArray.ConvertAll<DataGridViewCell, string>(r.Cells.Cast<DataGridViewCell>().ToArray, dgvc => dgvc.Value.ToString)where c.Contains(_txt)
                             select new  cell {
                            rowIndex = r.Index, 
                           columnIndex = Array.IndexOf(c, _txt) 
 };

foreach (DataGridViewRow r in dataGridView1.Rows.Cast<DataGridViewRow>()) {
    foreach (DataGridViewCell c in r.Cells.Cast<DataGridViewCell>()) {
        if (!r.IsNewRow) {
            c.Style.BackColor = Color.White;
        }
    }
}

foreach (object c_loopVariable in cells) {
    c = c_loopVariable;
    DataGridView1.Rows(c.rowIndex).Cells(c.columnIndex).Style.BackColor = Color.Red;
}

and changing the color of that cell.

And i want to find the first empty cell in datagridview i have (12 columns and 8 rows) my datagridview is filled by column wise. when it entering to the 8th row it is automatically goes to next column, Code is written below.Where _col and _row is declared globally

        dataGridView1[_col, _row].Value = lvI.Text;
                _row = _row + 1;
                if (_row == 8)
                {
                    _row = 0;
                    _col = _col + 1;
                }

actually i am filling datagridview from listview. when i check the listview item the datagridview is filled based on column wise. when i uncheck it clears the datagridview cell which contains that text.

i can show the picture of my datagridview for better understanding

after uncheck it will be like this

Answer 1

If you want to get all the cells containing some text, try this code, your old query has some dependency and you missed that part.

var cells = dataGridView1.Rows.Cast<DataGridViewRow>()
             .SelectMany(row=>dataGridView1.Columns.Cast<DataGridViewColumn>()
                              .Select(col=>row.Cells[col.Name]))
             .Where(cell=>Convert.ToString(cell.Value).Contains(textBox1.Text));

The cells is an IEnumerable<DataGridViewCell>

Then the code to change the BackColor can be like this:

foreach (var cell in cells) {
   cell.Style.BackColor = Color.Red;
}

Note that all the code you copied is useless.

To get the first empty cells, you do the same but with a different condition like this:

var firstEmptyCell = dataGridView1.Rows.Cast<DataGridViewRow>()
                    .SelectMany(row=>dataGridView1.Columns
                                    .Cast<DataGridViewColumn>()
                                    .Select(col=>row.Cells[col.Name]))
                    .OrderBy(cell=>cell.ColumnIndex)
                    .ThenBy(cell=>cell.RowIndex)
                    .FirstOrDefault(cell=>Convert.ToString(cell.Value) == "");
//The value of firstEmptyCell may be null if there is not any empty cell