How to select a TabItem based off of it's Header

Question

In my program I have a tabItem that gets selected when a TreeViewItem with an equivalent header is selected.

This is what I currently have (It works):

(parent_TreeViewItem.Items.Contains(SelectedItem))
{
          tabControl1.SelectedItem = tabControl1.Items //Changes tab according to TreeView
                .OfType<TabItem>().SingleOrDefault(n => n.Header.ToString() == SelectedItem.Header.ToString());
}

The difference with what I'm doing this time is that the tabItem's header that I'm selecting is composed of a string and an integer.

For example: The TreeViewItem selected will always have a header named "Arrival", but the tabItem's header will have a form like "Arrival" + integer. The integer value will come from the parent node's header.

For this process I'm thinking that I'll first need to get the header value of the parent node, since it contains that integer value I need. Then I'll need to modify my code above in someway to query for a node with a header like, "Arrival" + parentHeader.

How would I do something like this?

Thank you.

UPDATE

My current code, using @varocarbas's answer. I am using the first version of the answer that involved setting the integer curNumber to the value of the parent's header. The code compiles but does not do anything when the "Arrival" node is clicked on.

if (parent_TreeViewItem.Items.Contains(SelectedItem.Parent)) //Location - Actions tabs
{
       TreeViewItem parentItem = (TreeViewItem)SelectedItem.Parent;
       int curNumber = getNumber(parentItem.Header.ToString());

       tabControl1.SelectedItem = tabControl1.Items //Changes tab according to TreeView
             .OfType<TabItem>().SingleOrDefault(n => n.Header.ToString() == SelectedItem.Header.ToString() + curNumber.ToString());
}

public static int getNumber(string parentNodeHeader)
{
    int curNumber = 0;
    curNumber = Convert.ToInt32(parentNodeHeader);

    return curNumber;
}

UPDATE 2: Because the "Arrival" node is the grandchild of the node I was using as a parent I have changed the if statement in my first line to:

 if (parent_TreeViewItem.Items.Contains(SelectedItem.Parent))

Answer 1

Firstly, you have to get the parent node and the number contained in its header:

TreeViewItem parentItem = (TreeViewItem)selectedItem.Parent;
int curNumber = getNumber(parentItem.Header.ToString());

getNumber is a function to retrieve the number from its exact location in the parent node header. You have to tell more about that in order to write a proper function; for the time being, just the basics (it extracts all the numbers in the input string):

private int getNumber(string parentNodeHeader)
{
    int curNumber = 0;

    //Required string-analysis actions
    //Sample functionality: extract all the numbers in the given string
    string outString = "";
    int count = -1;
    do
    {
        count = count + 1;
        Char curChar = Convert.ToChar(parentNodeHeader.Substring(count, 1));
        if (Char.IsNumber(curChar))
        {
            outString = outString + parentNodeHeader.Substring(count, 1);
        }
    } while (count < parentNodeHeader.Length - 1);

    if (outString != "")
    {
        curNumber = Convert.ToInt32(outString);
    }

    return curNumber;
}

And then you have to update the query to account for the new information:

 .OfType<TabItem>().SingleOrDefault(n => n.Header.ToString() == selectedItem.Header.ToString() + curNumber.ToString());

UPDATE

The function above just shows the kind of code I usually rely on; but for simple situations (like the proposed one of getting all the numbers in a string), you might prefer to rely on Regex, as suggested by Viv. You might rely on something on the lines of:

private int getNumber(string parentNodeHeader)
{
    System.Text.RegularExpressions.Match m = System.Text.RegularExpressions.Regex.Match(parentNodeHeader, @"\d+");
    return Convert.ToInt32(m.Value);
}

This function only delivers the first set of consecutive numbers it finds; different result than the function above but enough as a proof of concept (intention of this answer).