Question

I am trying to change a variable value, but I only have the name of the variable as a string. I understand this is not generally ideal, but please assume it’s necessary for my situation. The variable I want to change is of type Element, a class I created that looks like this:

public class Element
    {
        public string TopBoundReplace;
        public string RightBoundReplace;
        public string BottomBoundReplace;
        public List<string> ConfidenceString {get; set;}
        public string LeftBoundReplace { get; set; }
        public string Regex { get; set; }
        public string ReplaceString { get; set; }
        public List<int> LeftBound { get; set; }
        public List<int> TopBound { get; set; }
        public List<int> BottomBound { get; set; }
        public List<int> RightBound { get; set; }
        public string Whitelist { get; set; }
        public List<System.Drawing.Rectangle> Rectangle { get; set; }
        public System.Drawing.Rectangle SourceBox { get; set; }
        public List<string> Value { get; set; }

        public Element()
            : this("", "", "", new List<int>(), new List<int>(), new List<int>(),new List<int>(), "", new List<Rectangle>(), new System.Drawing.Rectangle(), new List<string>(), new List<string>())
        {
        }
        public Element(string leftBoundReplace, string regex, string replaceString, List<int> leftBound, List<int> topBound, List<int> bottomBound, List<int> rightBound, string whitelist, List<System.Drawing.Rectangle> rectangle, System.Drawing.Rectangle sourceBox, List<string> value, List<string> confidenceString)
        {
            Regex = regex;
            ReplaceString = replaceString;
            LeftBound = leftBound;
            TopBound = topBound;
            BottomBound = bottomBound;
            RightBound = rightBound;
            Whitelist = whitelist;
            Rectangle = rectangle;
            SourceBox = sourceBox;
            Value = value;
            LeftBoundReplace = leftBoundReplace;
            ConfidenceString = confidenceString;
        }
    }

The Elements are initialized in another class, called ocrVar which looks like this (trimmed for the purposes of this question):

public class ocrVar
{
    public static Element DueDate = new Element();
    public static Element AmountDue = new Element();
    public static Element BillDate = new Element();
}

So, normally, I would edit the value in question by doing something like this:

ocrVar.DueDate.Value[0] = "10/25/2012";

How can I do this with just the string value as the variable name? I have tried some Reflection stuff:

Type myType = ocrVar.BillDate.GetType();
PropertyInfo myPropInfo = myType.GetProperty("DueDate");

myType ends up getting the correct type (Element), but myPropInfo remains null when running the above code because “DueDate” is not a property of the Element class, it’s a property of the ocrVar class. I would like to do something like the above code to get the values in the DueDate Element so I could manipulate the values, then put them back into ocrVar.DueDate.

Answer 1

You need to use FieldInfo and GetField instead of PropertyInfo and GetProperty, because your ocrVar.DueDate is a field, not a property.

This code gets the ocrVar.DueDate field into an Element variable. Is that what you want to do?

Type myType = typeof(ocrVar);
FieldInfo myPropInfo = myType.GetField("DueDate");
Element value = (Element)myPropInfo.GetValue(null);  // null because it's static