用整数在C＃中增加名称

Question

I need to get an object and check if it already exists.

In case it does, I want to add a number, or increase the number in its name. For example if I have the object "a" and it exists, I need to add a 1 so it's called a1. In case a1 exists, a2, etc.

How could I perform this?

My code:

if (e.TreeNode.Tag is Variant)
{
    if (variantExists(e.TreeNode.Text))
    {
        Random r = new Random();
        int randomNumber = r.Next(0, 99);
        e.TreeNode.Text = e.TreeNode.Text + randomNumber;
        //e.TreeNode.Remove(); 
        return;
    }
}

Answer 1

Can you change the TreeNode class? I would add properties for Label (Name without Index) and Index and make the Name property read only, ie

class TreeNode
{
    public int Index {get;set;}
    public string Label {get;set;}

    public string Name 
    {
        get { return Index == 0 ? Label : Label + Index; }
    }
}

In your code you just need to set the Index property to the value you need and dont worry about the whole string parsing stuff

Answer 2

string name = "SomeName";

string tempName = name;
int n = 0;

while (DoesNameExist(tempName))
{
    n++;
    tempName = name + n;
}

name = tempName;

This gets ineffecient for large numbers of the same object, but that shouldn't happen right?

The problem with doing it the other way around, and stripping off trailing numbers to find the "original" name is that the original name may genuinely have numbers on it.

Eg. You say you add:

SomeName
SomeName99
SomeName
SomeName99

The above code will give you

SomeName
SomeName1
SomeName99
SomeName991

Answer 3

Something along the lines of this could work:

var existingItems = new HashSet<string>();
var items = new List<string>{"a", "b", "a"};
foreach (var item in items)
{
    var tempItem = item;
    var i = 1;
    while (!existingItems.Add(tempItem))
        tempItem = tempItem + i++;
}