[英]WP7 - Access to the database file is not allowed
這是我的課:
[Table]
public class Question
{
[Column]
public bool Sort { get; set; }
[Column(IsPrimaryKey = true)]
public int QuestionID { get; set; }
[Column]
public int Level { get; set; }
[Column]
public string Description { get; set; }
[Column]
public string Answer1 { get; set; }
[Column]
public string Answer2 { get; set; }
[Column]
public string Answer3 { get; set; }
[Column]
public string Answer4 { get; set; }
[Column]
public string RightAnswer { get; set; }
[Column]
public bool Show { get; set; }
}
public class QuestionContext : DataContext
{
public QuestionContext(string connectionString)
: base(connectionString)
{
}
public Table<Question> Questions
{
get
{
return this.GetTable<Question>();
}
}
}
我正在嘗試連接到現有數據庫:
private const string ConnectionString = @"appdata:App_Data\QuestionDb.sdf";
public GamePage()
{
InitializeComponent();
using (QuestionContext context = new QuestionContext(ConnectionString))
{
if (!context.DatabaseExists())
{
// create database if it does not exist
context.CreateDatabase();
}
else
{
var questions = from o in context.Questions where o.Level == 1 && o.Show == false select o;
var question = questions.FirstOrDefault();
}
}
}
我收到“不允許訪問數據庫文件”錯誤。 我認為問題出在我的連接字符串中。 它出什么問題了? 如何訪問文件夾App_Data中的SQLCE數據庫?
在您的app.config中添加以下內容
<connectionStrings>
<add name="DataContext"
connectionString="Data source=DataDirectory|Database.sdf;"
providerName="System.Data.SqlServerCe.4.0"/>
</connectionStrings>
然后在ConfigurationManager的幫助下獲取連接字符串。 也許您需要添加對System.Configuration的引用。
private const string ConnectionString = ConfigurationManager.ConnectionStrings["DataContext"].ConnectionString
您可以在這里在ConnectionString中了解有關DataDirectory的更多信息: http : //msdn.microsoft.com/zh-cn/library/cc716756( v=vs.100) .aspx
您必須像這樣編寫連接字符串:
MyDataContext db = new MyDataContext("Data Source = 'appdata:/mydb.sdf'; File Mode = read only;");
數據庫文件將是只讀的...
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