'未處理的異常：System.IO.FileNotFoundException: 無法找到文件“/Logins.txt”發(fā)生'嗨，新手在 xamarin c# 中制作了一個非?；镜牡卿?注冊系統(tǒng)，它使用來自 Systsem.IO 的 StreamReader 讀取帶有存儲的用戶名和密碼的文本文件。txt 文件與 .cs 文件本身位于同一目錄中，并且在解決方案資源管理器中可見。我試過輸入完整路徑但沒有成功，并以管理員身份運(yùn)行，以防萬一它與權(quán)限有關(guān)。有什么不對嗎？public partial class LoginPage : ContentPage{ public LoginPage() { InitializeComponent(); } List<string> user = new List<string>(); List<string> pass = new List<string>(); public void btnLogin_Clicked(object sender, EventArgs e) { //Read the txt StreamReader sr = new StreamReader("Logins.txt"); string line = ""; //Read every line until there is nothing in the next line while ((line = sr.ReadLine()) != null) { //Grab items within new lines separated by a space and chuck them into their array string[] components = line.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries); user.Add(components[0]); pass.Add(components[0]); } //Check entries are on the same line and match if (user.Contains(txtUsername.Text) && pass.Contains(txtPassword.Text) && Array.IndexOf(user.ToArray(), txtUsername.Text) == Array.IndexOf(pass.ToArray(), txtPassword.Text)) { Navigation.PushModalAsync(new HomeScreen()); } else DisplayAlert("Error", "The username or password you have entered is incorrect", "Ok"); } private void Cancel_Clicked(object sender, EventArgs e) { Navigation.PushModalAsync(new MainPage()); }}
1 回答
qq_遁去的一_1
TA貢獻(xiàn)1725條經(jīng)驗 獲得超8個贊
如果將Logins.txt文件更改為嵌入資源，則可以在運(yùn)行時從程序集中加載該資源，如下所示：
var assembly = IntrospectionExtensions.GetTypeInfo(typeof(LoginPage)).Assembly;
Stream stream = assembly.GetManifestResourceStream("YourAssembly.Logins.txt");
string text = "";
using (var reader = new System.IO.StreamReader (stream))
{
text = reader.ReadToEnd();
}
YouAssembly指的是構(gòu)建項目時將生成的程序集 (dll) 的名稱。如果你不知道這是什么，或者沒有改變它，它可能與項目同名。
Xamarin 文檔有一個很好的例子來說明這是如何完成的：Xamarin.Forms 中的文件處理
編輯：
在構(gòu)造函數(shù)中執(zhí)行此操作并處理內(nèi)容以便您可以進(jìn)行身份驗證處理的更完整示例。
但首先，讓我們定義一個 POCO 來保存用戶名/密碼的詳細(xì)信息：
public class UserCredentials
{
public string Username {get;set;}
public string Password {get;set;}
}
添加一個屬性來保存這個類：
List<UserCredentials> CredentialList {get;set;}
現(xiàn)在，在構(gòu)造函數(shù)中：
public LoginPage()
{
InitializeComponent();
// Read in the content of the embedded resource, but let's read
// each line to make processing a little easier
var assembly = IntrospectionExtensions.GetTypeInfo(typeof(LoginPage)).Assembly;
Stream stream = assembly.GetManifestResourceStream("YourAssembly.Logins.txt");
var textLines = new List<string>();
string line = null;
using (var reader = new System.IO.StreamReader (stream))
{
while ((line = sr.ReadLine()) != null)
{
textLines.Add(line);
}
}
// Init our cred list
this.CredentialList = new List<UserCredentials>();
// Read out the contents of the username/password combinations
foreach (var line in textLines)
{
// Grab items within new lines separated by a space and chuck them into their array
string[] components = line.Split(new[] {' '}, StringSplitOptions.RemoveEmptyEntries);
// Add the combination to our list
this.CredentialList.Add(new UserCredential
{
Username = user.Add(components[0]),
Password = pass.Add(components[0])
});
}
}
現(xiàn)在我們的登錄變得容易多了。以前，我們首先檢查用戶名/密碼是否都存在于我們的已知數(shù)據(jù)集中，然后檢查它們在兩個列表中是否位于相同的索引處。
public void btnLogin_Clicked(object sender, EventArgs e)
{
// Now can use linq to validate the user
// NOTE: this is case sensitive
if (this.CredentialList.Any(a => a.Username == txtUsername.Text && a.Password == txtPassword.Text))
{
// NOTE: you've only validated the user here, but aren't passing
// or storing any detail of who the currently logged in user is
Navigation.PushModalAsync(new HomeScreen());
}
else
{
DisplayAlert("Error", "The username or password you have entered is incorrect", "Ok");
}
}
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