How do i...how could I resolve this error(sqlite/C# connectionstring from app.settings)?

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====The Error====
 Changes = '((System.Data.SQLite.SQLiteConnection)cnn).Changes' threw an exception of type 'System.InvalidOperationException'
 ====App.Config===

 <?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <connectionStrings>
    <add name ="Default" connectionString="Data Source=.\DemoDB.db;Version=3;" providerName="System.Data.SqlClient"/>
  </connectionStrings>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
    </startup>
</configuration>

====My Code====
 public static List<DepartmentModel> LoadDepartment()
        {
            using (IDbConnection cnn = new SQLiteConnection(LoadConnectionString()))
            {
                var output = cnn.Query<DepartmentModel>("select * from Department", new DynamicParameters());
                return output.ToList();
            }
        }

        public static void SaveDepartment(DepartmentModel department)
        {
            using (IDbConnection cnn = new SQLiteConnection(LoadConnectionString()))
            {
                cnn.Execute("insert into Department (department_name,department_code, school_id) values (@DepartmentName,@DepartmentCode,@SchoolId)", department);
            }
        }

        private static string LoadConnectionString(string id = "Default")
        {
            return ConfigurationManager.ConnectionStrings[id].ConnectionString;
        }

What I have tried:

Single-stepping through,checked file path,

Posted 26-Aug-19 11:01am

Member 2575377

Updated 27-Aug-19 9:33am

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Comments

Richard MacCutchan 27-Aug-19 3:25am

You need to catch the exception and examine its contents to find out exactly what values/parameters/object reference is the cause of the problem. You also need to indicate which line it occurs on.

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dnxit · Answer 1 · 2019-08-27T09:34:00

You just need the path where file exists physically, here is an example

C#

private readonly SQLiteConnection _connection;
private Database()
{
	var databaseFile = GetDatabasePath();
	if (!File.Exists(databaseFile))
	{
		SQLiteConnection.CreateFile(databaseFile);
	}
	_connection = new SQLiteConnection($"Data Source={databaseFile};Version=3;");
}

we used Dapper for SQLite db communication.