鏈接：https://stackoverflow.com/questions/48043058/xamarin-forms-read-from-text-file-result-is-null

Stream stream = assembly.GetManifestResourceStream("Mapper.data.txt");

這樣直接寫讀取內(nèi)容為null, 需要在當(dāng)前程序集遍歷找到那個資源文件，然后再取。

Solution:

var assembly = typeof(MapPage).GetTypeInfo().Assembly;
foreach (var res in assembly.GetManifestResourceNames())
{
    if(res.Contains("data.txt"))
    {
        Stream stream = assembly.GetManifestResourceStream(res);

        using (var reader = new StreamReader(stream))
        {
            string htmlString = reader.ReadToEnd();            
        }
        break;
    }
}