按属性在列表中查找项目并知道项目名称

Question

I have struggled with figuring out how to find an item in a list by checking for a property and then isolating and naming this item. I need to do this to set a value that corresponds with that specific string. It wouldn't work if I just found that there is one, or several items in the list that match the property. My code is massive, but here's a snippet of it:

List<string> diag_right = new List<string>();
diag_right.Add(b3); //Add the string b3
diag_right.Add(b5); //Add the string b5
diag_right.Add(b7); //Add the string b7

if (diag_right.Exists(a => a.Equals("")))
{
    //Find the item (string name, b3, b5, etc.) that was found as matching the blank property
}

Is it possible to do this? I know I can do this by checking to see if each string matches this property individually, but is there a faster way to do this?

Answer 1

Many ways this can be achieved, I prefer simple approach, loop collection using index and modify matching field

for(int index=0; index< diag_right.Count(); index++)
{
    if(diag_right[index] == "b3")
    {
        // update               
        diag_right[index] = "b8";               
    }
}

Linq approach

This approach I just used Linq to fetch all indexes for a matching string.

var indexes = diag_right.Where(e=>e.Equals("searchstring")).Select((c,i) => i).ToList();

foreach(int index in indexes) // loop through each line.
{
     diag_right[index] = "newvalue"; // set new value.
}

Working Demo