Dynamic textboxes error Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

Question

Hello there im trying to save some data from dynamic textboxes into XML file. But everytime i try i get this error

"Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index"

XmlDocument document = new XmlDocument();
                document.Load(@"myGrades.xml");            
                for (int i = 0; i < 7; i++)
                {
                    **TextBox tb1 = (TextBox)textboxComputer[i];** //<- error is thrown here
                    string markGained = tb1.Text;
                    this.Text = markGained;
                    XmlElement root = document.DocumentElement;
                    XmlElement newAssessmentMark = document.CreateElement("Assessment");
                    XmlElement newMark = document.CreateElement("AssessmentMark");
                    XmlText mark = document.CreateTextNode(markGained);
                    newAssessmentMark.AppendChild(newMark);
                    newMark.AppendChild(mark);
                    XmlNode parentNode = document.SelectSingleNode("myGrades/courseStructure/level4");
                    parentNode.InsertAfter(newAssessmentMark, parentNode.LastChild);

                    document.Save(@"myGrades.xml");

                }

                this.Close();

Help appreciated :)

Answer 1

textboxComputer seems to be an array, so in your for loop do:

for( int i = 0; i < textboxComputer.Length; i++ ) ...

Alternatively you can pre-compute it:

int length = textboxComputer.Length;

for( int i = 0; i < length; i++ ) ...