有什么方法可以使字典存储价值而不是指向价值？

Question

So I have a dictionary:

var tableVars = new Dictionary<string, TableDLL.tableObject>();

And the tableObject class:

public class tableObject
    {
        public string Name { get; set; }
        public string Type { get; set; }
        public string Value { get; set; }
        public string Default { get; set; }
    }

And I go through this loop:

var obj = new TableDLL.tableObject();
        foreach (XmlNode nodes in root.ChildNodes)
        {
            obj.Value = nodes.InnerText;
            tableVars.Add(nodes.Name, obj);
        }

When the loop is complete, I have 65 different Dictionary entries, but they are all pointing to the LAST obj that is made in the loop. What would be the best way to get the Dictionary to store the value, rather than simply pointing to it (and therefore changing with changes to obj )? Do I have to make a new TableDLL.tableObject for each Dictionary entry?

Answer 1

Move the creation of obj into the loop:

    foreach (XmlNode nodes in root.ChildNodes)
    {
        var obj = new TableDLL.tableObject();
        obj.Value = nodes.InnerText;
        tableVars.Add(nodes.Name, obj);
    }

Otherwise you are adding the same object multiple times.

Answer 2

You're only creating a single object and continually updating Value with the last node. With the correction, you're creating N objects with the appropriate Value .

This:

    var obj = new TableDLL.tableObject();
    foreach (XmlNode nodes in root.ChildNodes)
    {
        obj.Value = nodes.InnerText;
        tableVars.Add(nodes.Name, obj);
    }

should be this:

    foreach (XmlNode nodes in root.ChildNodes)
    {
        var obj = new TableDLL.tableObject();
        obj.Value = nodes.InnerText;
        tableVars.Add(nodes.Name, obj);
    }

Answer 3

You just have to create it in the loop:

foreach (XmlNode nodes in root.ChildNodes)
{
    var obj = new TableDLL.tableObject();
    obj.Value = nodes.InnerText;
    tableVars.Add(nodes.Name, obj);
}

Otherwise you're always adding the same object.

Answer 4

You've only created 1 object, so there is no possibility for the list to have 65 different objects.

Basically, what you did is:

1. Take a box.
2. Put something in the box.
3. Now replace that thing with another thing.

You haven't created a new container, you just changed the existing container's contents.

Do it like this:

    foreach (XmlNode nodes in root.ChildNodes)
    {
        var obj = new TableDLL.tableObject();
        obj.Value = nodes.InnerText;
        tableVars.Add(nodes.Name, obj);
    }

The difference being:

1. Take a box.
2. Put something in the box.
3. Now take a new box.
4. Put the other thing in the new box
5. etc...

If you want 65 tableObject objects, you will need to call new tableObject(); 65 times. Else you're just reusing the original object.

Feel free to ask for more information if you need it.

Answer 5

Create a new copy of your tableObject each time round the loop.

    foreach (XmlNode nodes in root.ChildNodes)
    {
        var obj = new TableDLL.tableObject();
        obj.Value = nodes.InnerText;
        tableVars.Add(nodes.Name, obj);
    }