C# - 使用 File.Exists，当文件不存在时不运行最后一个 else 语句

Question

Super new to C#. I'm having an input get split and then find an ID from the pointsTarget var. When the file DOES exist, it seems that the line "else if (File.Exists(filePath+userId+txt))" returns "true" because it runs just fine and sets the argument "addPointsCompleted" to TRUE. It works just how I would expect. But when the file does NOT exist, I want it to return false and run the last else statement: CPH.SetArgument("missing", "True"); and set "missing" to TRUE.

I feel like there is something wrong with the way I put in the if/else if/else statement because I get an error "System.IO.FileNotFoundException: Could not find file 'E:\Users\Troy\Documents\Stuff\PointNames\Test.txt'.

using System;
using System.IO;

public class CPHInline
{
    public bool Execute()
    {
        string rawInput = args["rawInput"].ToString();
        string[] split= rawInput.Split('+');
        var pointsTarget = split[0].ToString();
        var addPoints = split[1].ToString();
        CPH.LogInfo($"pointsTarget is {pointsTarget}");
        CPH.LogInfo($"addPoints is {addPoints}");
        var user = args["user"].ToString();
        CPH.SetArgument("pointsTarget", pointsTarget);
        string userPath = @"E:/Users/Troy/Documents/Stuff/PointNames/";
        string filePath = @"E:/Users/Troy/Documents/Stuff/PointIDs/";
        string txt = ".txt";
        var userId = File.ReadAllText(userPath+pointsTarget+txt);
        CPH.LogInfo($"userId is {userId}");

        if (user == pointsTarget)
        {
            CPH.SetArgument("corrupt", "True");
        }
        else if (File.Exists(filePath+userId+txt))
        {
            //DO THIS
            string fileName = filePath+userId+txt;
            string points = File.ReadAllText(fileName);
            int x = Convert.ToInt32(points);
            int y = Convert.ToInt32(addPoints);
            int sum = x + y;
            String newPoints;
            newPoints = sum.ToString();
            File.WriteAllText(fileName, newPoints);
            CPH.SetArgument("newPoints", newPoints);
            CPH.SetArgument("addPointsCompleted", "True");
        }
            
        else
        {
            //do this
            CPH.SetArgument("missing", "True");
        }

        return true;

     
    }
}

I tried looking around, but all the issues are from people where the file DOES exist and they can't find it. My problem is kind of the opposite.

Answer 1

I feel like there is something wrong with the way I put in the if/else if/else statement because I get an error "System.IO.FileNotFoundException: Could not find file 'E:\Users\Troy\Documents\Stuff\PointNames\Test.txt'.

This is a good opportunity for you to start familiarizing yourself with using a debugger to step through the code and observe its behavior. Because the problem has nothing to do with your if structure. It's happening before your if block. Right here:

var userId = File.ReadAllText(userPath+pointsTarget+txt);

Look at the error message. It's trying to read a file in the "PointNames" folder. Which is in your userPath variable:

string userPath = @"E:/Users/Troy/Documents/Stuff/PointNames/";

Which is only ever used in that one line of code that tries to read a file. And File.ReadAllText will throw a FileNotFoundException if the file is not found.

It seems you're already aware of how to check if a file exists. So why not apply that here? For example:

var userId = string.Empty;
if (File.Exists(userPath+pointsTarget+txt))
{
    userId = File.ReadAllText(userPath+pointsTarget+txt);
}
else
{
    // handle the error in some way
}