/// <summary>
/// REQUIREMENT: Variable names must be formatted as: "[column letter][row number]"
/// Defines cell variables in the expression tree and subscribes the
/// current cell to each variable cell's property changed event.
/// </summary>
/// <param name="et">Expression tree.</param>
/// <param name="currCell">Current spreadsheet cell.</param>\
/// <returns>If there was an error.</returns>
private bool HandleCellVariables(ExpressionTree et, SpreadsheetCell currCell)
{
bool variableError = false;
List <string> variableNames = et.GetVariableNames();
foreach (string name in variableNames)
{
SpreadsheetCell varCell = this.GetCellFromName(name);
if (varCell == null)
{
currCell.SetValue("!(bad reference)");
variableError = true;
}
else if (varCell == currCell)
{
currCell.SetValue("!(self reference)");
variableError = true;
}
else if (this.ContainsCircularReference(currCell, varCell))
{
currCell.SetValue("!(circular reference)");
variableError = true;
}
else
{
// If the cell's value string cannot be parsed as a double, defaults to 0.
double value = 0.0;
try
{
value = double.Parse(varCell.Value);
}
catch (FormatException) { }
et.SetVariable(name, value);
currCell.SubToCellChange(varCell);
}
}
return(variableError);
}
// Clears out entire spreadsheet
public void ClearSheet()
{
for (int i = 0; i < ColumnCount; i++)
{
for (int j = 0; j < RowCount; j++)
{
SpreadsheetCell temp = (SpreadsheetCell)cells[i, j];
temp.Text = null;
temp.SetValue(null);
}
}
}
/// <summary>
/// Updates (and possibly evaluates) a cell's value.
/// </summary>
/// <param name="cell">Spreadsheet cell.</param>
private void UpdateCellValue(SpreadsheetCell cell)
{
string newValue = cell.Text;
if (newValue.StartsWith("="))
{
newValue = this.EvaluateCellExpression(cell).ToString();
}
cell.SetValue(newValue);
this.CellPropertyChanged?.Invoke(cell, new PropertyChangedEventArgs("Value"));
}
