//function that evaluates the expression inside the cell and returns the value as double
private void UpdateCellValue(SpreadsheetCell c)
{
//get the expression inside the cell
string expression = c.newCellText;
string cellName = Number2String(c.getColumn + 1, true);
cellName += (c.getRow + 1).ToString();
string vari = "";
//parse the string in the exptree class taking out the = sign in the front of exp
ExpTree tree = new ExpTree(expression.Substring(1));
//delete thr reference cells
c.listOfCells.Clear();
//get all the variables inside the dictionary
string[] variables = tree.getVar();
foreach (string variable in variables)
{
if (variable.Length > 2)
{
vari = variable;
break;
}
//all the columns are marked from A to Z so we have to convert that to int
int col = Convert.ToInt32(variable[0] - 65);
// remaining part is the name of the cell we need to copy a value from
//to convert that
int row = Convert.ToInt32(variable.Substring(1)) - 1;
//add it to the reference cell list
c.addReferences(SS_Array[row, col]);
if (string.IsNullOrEmpty(SS_Array[row, col].newCellText))
{
c.newCellText = "0";
c.Value = "0";
break;
}
if (variable == cellName)
{
vari = variable;
break;
}
tree.SetVar(variable, double.Parse(SS_Array[row, col].cellValue));
SS_Array[row, col].PropertyChanged += c.OnVariableChange;
}
if (vari == cellName)
{
c.newCellText = "!(Self/Circular reference)";
c.Value = "!(Self/Circular reference)";
}
else if (vari.Length > 3)
{
c.newCellText = "!(Bad reference)";
c.Value = "!(Bad reference)";
}
else
{
//evaluate the expression
double newVal = tree.Eval();
c.Value = newVal.ToString();
}
}
