Xamarin SQLite报错：System.DllNotFoundException问题求助

Hey there, let's break down your two problems and fix them step by step!

This error usually stems from platform-specific SQLite library mismatches or incorrect setup. Here are actionable solutions:

• Verify SQLite Library References
  If you're using NuGet packages like sqlite-net-pcl or Microsoft.Data.Sqlite, double-check that these packages are installed across all your projects (including platform-specific ones like your Android project). Many SQLite bindings rely on platform-native libraries, and missing the right package will cause the libsqlite.so not found error.

• Check Android Native Library Deployment
  For Android, ensure the libsqlite.so file exists in the correct architecture directories (e.g., armeabi-v7a, arm64-v8a) within your Android project. If you added the library manually, set its Build Action to AndroidNativeLibrary so it gets packaged into the APK correctly.

• Avoid Direct Native SQLite3 Calls
  Your current code calls SQLite3.Open() directly, which bypasses higher-level platform handling. Switch to using a mature wrapper like SQLiteConnection from sqlite-net-pcl—it automatically handles native library loading and path adaptation, eliminating the need to call low-level APIs manually.

• Validate Database Path
  While this error is about the library, invalid paths can sometimes trigger indirect loading issues. Ensure your database path points to an Android-accessible directory (like the app's private data folder):

  var validPath = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
  

From the code snippet you shared, there are a few key improvements and checks to make:

1. Add Proper Exception Handling #

Your try block lacks a catch clause—without it, any error will crash the app instead of returning false. Add a catch to handle failures gracefully.

2. Use a Valid, Permission-Safe Path #

Don't rely on a custom folder variable unless you're certain it's an Android-accessible directory. Use the system-provided private data folder to avoid permission issues.

3. Complete & Optimize CreateTable #

Use CreateFlags to ensure all necessary constraints (like indexes or foreign keys) are created if your Portfolio class requires them.

Corrected Function Example #

public bool CreateDatabase() { 
    try { 
        // Use app's private data directory to avoid permission problems
        var dbPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "CryptoSimulator.db");
        using (var connection = new SQLiteConnection(dbPath)) { 
            // Create table with implicit constraints/indexes
            connection.CreateTable<Portfolio>(CreateFlags.AllImplicit); 
            return true; // Return true on success
        }
    } catch (Exception ex) {
        // Log the error for debugging (e.g., Console.WriteLine(ex.ToString()))
        return false; // Return false if any step fails
    }
}

Quick Check for Portfolio Class #

Ensure your Portfolio model follows SQLite-net conventions, like having a primary key:

public class Portfolio {
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }
    // Other properties...
}

内容的提问来源于stack exchange，提问作者user9198450