如何解决“方法'Replace'没有重载需要'1'个参数”

Question

I want to replace a string that contains "Left" with "Right", the old code simply replaces "Left" with "R", I looked online for various solutions with no luck and keep the error "No overload for method 'Replace' takes '1' arguments",(I didn't write this) Here is a sample of the code:

 public void FlipLRXsp()
    {
        if (this.parentSurvey.SectionEditing != true)
        {
            throw new Exception("Trying to flip XSP outside section editing.");
        }

        bool changed = false;

        foreach (NvoItem item in this.ItemList)
        {
            string xsp = item.Xsp.ToUpper();
            if (xsp.Contains("Left") == true)
            {
                # old code item.Xsp = xsp.Replace('R', 'L');
                # new code item.Xsp = xsp.Replace("Right");
                changed = true;
            }
            else if (xsp.Contains("Right") == true)
            {
                item.Xsp = xsp.Replace('L', 'R');
                changed = true;
            }
        }

        if (changed == true) this.IsModified = true;
    }

Answer 1

That's because of this line of code

item.Xsp = xsp.Replace("Right");

You need to tell the method which (1st param) to replace with what (2nd param). Try this code, it replaces all "Left" occurrences with "Right".

item.Xsp = xsp.Replace("Left", "Right");

Answer 2

In C#, Replace(oldValue, newValue) expects 2 values, oldValue will be replaced with newValue .

There are multiple mistakes in your code. Please go through comments in below code. Also decide if you really need to use .ToUpper()

    public void FlipLRXsp()
    {
        if (this.parentSurvey.SectionEditing != true)
        {
            throw new Exception("Trying to flip XSP outside section editing.");
        }

        bool changed = false;

        foreach (NvoItem item in this.ItemList)
        {
            string xsp = item.Xsp.ToUpper();
            // ToUpper converts all letters to capital, 
            // so compare with 'LEFT' and 'RIGHT'
            if (xsp.Contains("LEFT")) // .Contains() method returns boolean value, so comparison with 'true' is not needed
            {
                # old code item.Xsp = xsp.Replace('R', 'L'); // this replaces only single character
                # new code item.Xsp = xsp.Replace("Right");
                item.Xsp = xsp.Replace("LEFT", "RIGHT"); // replace LEFT with RIGHT
                changed = true;
            }
            else if (xsp.Contains("RIGHT"))
            {
                item.Xsp = xsp.Replace('RIGHT', 'LEFT'); // replace RIGHT with LEFT
                changed = true;
            }
        }

        if (changed) 
        { 
            this.IsModified = true;
        }
    }