Selecting cells and objects using code

The Selection property is read-write, so you can easily select cell ranges using code. You can also perform selections using the Select method, just like in the C1FlexGrid for WinForms. The Select method allows you to select cells or ranges, and optionally scroll the new selection into view so the user can see it.

For example, to select the first cell in the grid and make sure it's visible to the user, you could use this code:

// select row zero, column zero, make sure the cell is visible
fg.Select(0, 0, true);

The selection methods all work based on row and column indices. But you can use them to make selections based on cell content as well. For example, the code below will select the first row that contains a given string in the grid's "Name" column:

bool SelectName(string name)
{
  // find row that contains the given string in the "Name" column
  int col = _flexGroup.Columns["Name"].Index;
  int row = FindRow(_flex, name, _flex.Selection.Row, col, true);
  if (row > -1)
  {
    _flex.Select(row, col);
    return true;
  }

  // not found...
  return false;
}

The code uses a FindRow helper method defined below:

// look for a row that contains some text in a specific column
int FindRow(C1FlexGrid flex, string text,
            int startRow, int col, bool wrap)
{
  int count = flex.Rows.Count;
  for (int off = 0; off <= count; off++)
  {
    // reached the bottom and not wrapping? quit now
    if (!wrap && startRow + off >= count)
    {
      break;
    }

    // get text from row
    int row = (startRow + off) % count;
    var content = flex[row, col];

    // found? return row index
    if (content != null &&
        content.ToString().IndexOf(text,
        StringComparison.OrdinalIgnoreCase) > -1)
    {
      return row;
    }
  }

  // not found...
  return -1;
}

The FindRow method given above implements the functionality provided by the FindRow method in the WinForms version of the C1FlexGrid. That method is not built into the Silverlight version of the grid in order to keep the control footprint small. The method searches a given column for a string, starting at a given row and optionally wrapping the search to start from the top if the string is not found. It is flexible enough to be used in many scenarios.

Another common selection scenario is the case where you want to select a specific object in the data source. Your first impulse might be to find the index of the object in the source collection using the PagedCollectionView.IndexOf method, then use the index to select the row. The problem with that approach is it will work only if the data is not grouped. If the data is grouped, the group rows also count, so the indices of items in the data source do not match the row indices on the grid.

The easy way to solve this problem is to enumerate the rows and compare each row's DataItem property to the item you are looking for. The code below shows how this is done:

var customer = GetSomeCustomer;

#if false // ** don't use this, won't work with grouped data

  int index = view.IndexOf(customer);
  if (index > -1)
  {
    _flex.Select(index, 0);
  }

#else // this is the safe way to look for objects in the grid

  for (int row = 0; row <= _flex.Rows.Count; row++)
  {
    if (row.DataItem == customer)
    {
      _flex.Select(row, 0);
      break;
    }
  }
#endif