//cell Property change handler
private void HandlePropertyChanged(object sender, PropertyChangedEventArgs e)
{
AbstractCell cell = (AbstractCell)sender;
switch (e.PropertyName)
{
case "Text":
cell.EvaluatedValue = changedCellStringContents(cell);
break;
case "Value":
//TODO:
break;
default:
break;
}
NotifyCellPropertyChanged(cell);
}
//Used to update a cell's evaluated text value, defined recursively to allow for nested references (e.g. B1 = B2, B2 = B3, B3 = "5")
private string changedCellStringContents(AbstractCell cell)
{
if (cell.TextValue.First() != '=')
{
return(cell.TextValue);
}
else
{
ExpTree expTree = new ExpTree(cell.TextValue.Substring(1));
List <ExpTree.VarNode> variableNodeList = expTree.variablesNodes();
foreach (ExpTree.VarNode varNode in variableNodeList)
{
int column = ((int)varNode.getName()[0] - 64) - 1;
int row = int.Parse(varNode.getName().Substring(1)) - 1;
string temp = cells[row, column].EvaluatedValue;
if (temp.Length == 0)
{
return("#REF!"); //Refernce Error
}
varNode.setValue(Double.Parse(cells[row, column].EvaluatedValue));
}
//Unsubscribe from the following Cells
foreach (AbstractCell subCell in cell.SubscribedToCells)
{
subCell.PropertyChangedValue -= (PropertyChangedEventHandler)cell.HandleValuePropertyChanged;
}
//Executed separately to ensure no cells are subrscribed if a reference error occurs
foreach (ExpTree.VarNode varNode in variableNodeList)
{
int column = ((int)varNode.getName()[0] - 64) - 1;
int row = int.Parse(varNode.getName().Substring(1)) - 1;
cells[row, column].PropertyChangedValue += new PropertyChangedEventHandler(cell.HandleValuePropertyChanged);
//Record which cells we're subbed to
cell.SubscribedToCells.Add(cells[row, column]);
}
return(expTree.Eval().ToString());
//return changedCellStringContents(cells[row, column]);
}
}
//Event used to alert UI-layer code to update the content of a cell
public void NotifyCellPropertyChanged(AbstractCell cell)
{
CellPropertyChanged?.Invoke(cell, new PropertyChangedEventArgs("Cell"));
}
