如何修复Xamarin.forms System.IO.FileNotFoundException:找不到文件 [英] how to fix Xamarin.forms System.IO.FileNotFoundException: Could not find file

问题描述

我正在使用 xamrin.forms ，并且正在尝试访问文件并读取它.

I am using xamrin.forms, and I am trying to access file and read it.

我将lastusername.txt作为文本文件，并将其构建操作设置为"Content"，实际上我正在尝试按以下方式读取文件:

I have lastusername.txt as text file and I set the build action for it as "Content", actually I am trying to read file as the following:

  var filename = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "lastusername.txt");
    if (filename != null)
           return System.IO.File.ReadAllText(filename);//error occurred here 
    else
           return "";

我收到以下错误:

System.IO.FileNotFoundException:找不到文件

System.IO.FileNotFoundException: Could not find file

推荐答案

将文件放置在Android Assets 文件夹中，并将其分配给构建类型为"AndroidAsset".

Place your file within the Android Assets folder and assign it with a build type of "AndroidAsset".

由于您的应用程序资产是只读的，因此您可以通过AssetManager对其进行读取，如果不存在(例如，该应用程序首次运行)，则可以将其保存(复制)到其他位置:

Since your app's assets are read-only, you can then read it via the AssetManager, saving (copy) it somewhere else if it does not exist (i.e. the first time the app is run):

var fileName = "MyAssetBasedFile.txt";
if (!File.Exists(Path.Combine(CacheDir.Path, fileName)))
{
    AssetManager assets = this.Assets;
    using (StreamReader sr = new StreamReader(assets.Open(fileName)))
    using (StreamWriter sw = new StreamWriter(Path.Combine(CacheDir.Path, fileName), append: false))
        sw.Write(sr.ReadToEnd());
}
string content;
using (StreamReader sr = new StreamReader(Path.Combine(CacheDir.Path, fileName)))
{
    content = sr.ReadToEnd();
}
Log.Debug("SO", content);

下次运行该应用程序时，您将在缓存目录中找到一个.

The next time the app runs you will pick up the one in your cache dir.

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