Sending Text One Character at a time fails with "cannot convert from char to string"

I am trying to send a string one character at a time. When I try the code below it isn’t working. It says Argument 1: cannot convert from char to string. I know this is probably something simple I am not doing, I just can’t think of what it is.

    public void SelectUnit(string unitStr)
    {
        // Enter the text for the search
        new LufasWebManager().Stall(500);
        for (int i = 0; i < unitStr.Length; i++)
        {
            unitTxt.SendText(unitStr[i]);
            Thread.Sleep(10);
        }
        
        new LufasWebManager().Stall(2000);

        // Locate the correct result
        var unitSearchResult = driver.FindElement(By.XPath($"//lfs-search-results-drop-list/div/div/div[contains(text(), '{unitStr}')]"));

        // And then click it
        unitSearchResult.Click();
    }

It is not working when I try the unitStr[i].

>Solution :

cannot convert from char to string

So send a string:

unitTxt.SendText(unitStr[i].ToString());