// Function that updates all the cells of a circular reference to 0
// Excel has the feature set up this way, so I decided to mimic this
// NOTE:
// It's not extensive. For example, if cell B1 holds A1+A2, and A1 holds a
// circular reference, then B1 will not be changed. But any cells that have a
// direct reference (i.e. some cell's value =A1) on A1 will be set to 0
public void updateCells(string originalCell)
{
foreach (var cell in dependencies)
{
// we have already editted the text of the cell passed in to "!(Circular Reference)"
// so we continue to the next item in the dictionary of dependencies
if (originalCell == cell.Key)
{
continue;
}
// get the cell based on the key
m_Cell dependentCell = GetCell(cell.Key) as m_Cell;
// set value and fire property changed
dependentCell.setValue("0");
SSPropertyChanged(dependentCell, new PropertyChangedEventArgs("Value"));
}
}
public void EvalCell(Cell CellArg)
{
m_Cell m_c = CellArg as m_Cell;
if (string.IsNullOrEmpty(m_c.Text))
{
m_c.setValue("");
SSPropertyChanged(CellArg, new PropertyChangedEventArgs("Value"));
}
else if (m_c.Text[0] == '=' && m_c.Text.Length > 1)
{
bool flag = false;
string expStr = m_c.Text.Substring(1);
// set the expression string and create the tree
ExpTree exp = new ExpTree(expStr);
// gets expression variables
string[] expVars = exp.GetVarNames();
// sets each variable in the expression
foreach (string varName in expVars)
{
// check if the cell is valid
if (GetCell(varName) == null)
{
// set value to the error and fire property changed event for the value
m_c.setValue("!(Bad Reference)");
SSPropertyChanged(m_c, new PropertyChangedEventArgs("Value"));
flag = true;
break;
}
// check to see if its a self reference
if (varName == m_c.Name)
{
// set value to the error and fire property changed event for the value
m_c.setValue("!(Self Reference)");
SSPropertyChanged(m_c, new PropertyChangedEventArgs("Value"));
flag = true;
break;
}
// valid variable
SetExpVariable(exp, varName);
// check for circular reference after we've determined its a valid reference
if (CheckCircularRef(varName, m_c.Name))
{
// set value to the error and fire property changed event for the value
m_c.setValue("!(Circular Reference)");
SSPropertyChanged(m_c, new PropertyChangedEventArgs("Value"));
updateCells(m_c.Name);
flag = true;
break;
}
}
if (flag)
{
return;
}
// Sets the expression evaluation to the current cells value and fires the property changed event
m_c.setValue(exp.Eval().ToString());
SSPropertyChanged(CellArg, new PropertyChangedEventArgs("Value"));
}
else // no equals sign present so change the text
{
m_c.setValue(m_c.Text);
SSPropertyChanged(CellArg, new PropertyChangedEventArgs("Value"));
}
if (dependencies.ContainsKey(m_c.Name))
{
foreach (string name in dependencies[m_c.Name])
{
EvalCell(name);
}
}
}
