private bool CircularReferenceChecker(CellClass cell, List <CellClass> cells)
{
if (cell.Text == string.Empty)
{
return(false);
}
if (cell.Text[0] != '=')
{
return(false);
}
ExpressionTree expression = new ExpressionTree(cell.Text.Substring(1));
List <string> variableList = expression.GetVariableNames();
if (cells.Contains(cell))
{
return(true);
}
cells.Add(cell);
List <CellClass> cellList = new List <CellClass>();
foreach (string variable in variableList)
{
cellList.Add(this.GetCellFromIndex(variable));
}
foreach (CellClass cellClass in cellList)
{
if (cellClass != null)
{
if (cellClass.Text != " " || cellClass.Text != null)
{
var newCellList = new List <CellClass>(cells);
if (this.CircularReferenceChecker(cellClass, newCellList))
{
return(true);
}
}
}
}
return(false);
}
/// <summary>
/// Function initialize the expression tree
/// and set the cell reference for the expression tree.
/// </summary>
/// <param name="expression"> expression that needs to be evaluated.</param>
public void InitializeTree(string expression)
{
this.expression = new ExpressionTree(expression);
this.expression.SetCellForTree(this);
}
/// <summary>
/// envent to change cell.
/// </summary>
/// <param name="sender">sender.</param>
/// <param name="e">e.</param>
private void CellPropertyChanges(object sender, PropertyChangedEventArgs e)
{
SpreadsheetCell spreadsheet = sender as SpreadsheetCell;
Dictionary <int, char> alp = new Dictionary <int, char>();
int count = 0;
for (char i = 'A'; i <= 'Z'; i++)
{
alp[count] = i;
count++;
}
string changeCell = alp[spreadsheet.ColumIndex].ToString() + (spreadsheet.RowIndex + 1).ToString();
if (e.PropertyName == "Text")
{
if (spreadsheet.Text.StartsWith("=") == false)
{
spreadsheet.Value = spreadsheet.Text;
}
else
{
// if equal to the expreesion which need to cal by expression tree.
if (spreadsheet.Text.Length > 3)
{
string expression = spreadsheet.Text.Substring(1);
ExpressionTree tree = new ExpressionTree(expression);
List <string> strlist = tree.GetVaribles(expression);
foreach (string var in strlist)
{
SpreadsheetCell cell = this.GetSingleValue(var);
if (cell != null)
{
if (this.GetSingleValue(changeCell) == this.GetSingleValue(var))
{
spreadsheet.Value = "!self reference";
}
else if (this.GetSingleValue(var).Value != "!self reference")
{
double value = Convert.ToDouble(this.GetSingleValue(var).Value);
tree.SetVariable(var, value);
spreadsheet.Value = tree.Evaluate().ToString();
}
else
{
spreadsheet.Value = Convert.ToString(0);
}
cell.PropertyChanged += spreadsheet.CellPropertyChanged;
}
else
{
spreadsheet.Value = "!bad reference";
}
}
}
// if = like B1,A1 just single cell value.
else
{
string name = spreadsheet.Text.Substring(1);
SpreadsheetCell cell = this.GetSingleValue(name);
// cell will be null if catch FormatException case which return to null,if not, just normall to get value else will be bad reference.
if (cell != null)
{
// if equal self cell value
if (this.GetSingleValue(changeCell) == this.GetSingleValue(name))
{
spreadsheet.Value = "!self reference";
}
// if equal the cell value which is no self reference, else is equal zero.
else if (this.GetSingleValue(name).Value != "!self reference")
{
spreadsheet.Value = this.GetSingleValue(name).Value;
}
else
{
spreadsheet.Value = Convert.ToString(0);
}
cell.PropertyChanged += spreadsheet.CellPropertyChanged;
}
else
{
spreadsheet.Value = "!bad reference";
}
}
}
}
this.CellPropertyChanged?.Invoke(sender, new PropertyChangedEventArgs("Value"));
}
public void TestVariableDefaultZero()
{
var tree = new ExpressionTree("alpha+beta");
Assert.AreEqual(tree.Variables.Length, 2);
}