C# 创建SQLite数据库时发生异常
我开发了一个使用本地SQLite数据库的通用应用程序。因为我需要知道数据库版本,所以我存储了一个包含此信息的附加信息 在应用程序启动时,我检查数据库是否存在,以及数据库版本是否已更改C# 创建SQLite数据库时发生异常,c#,sqlite,exception,windows-phone,windows-phone-8.1,C#,Sqlite,Exception,Windows Phone,Windows Phone 8.1,我开发了一个使用本地SQLite数据库的通用应用程序。因为我需要知道数据库版本,所以我存储了一个包含此信息的附加信息 在应用程序启动时,我检查数据库是否存在,以及数据库版本是否已更改 public sealed partial class App : Application { // DB Name public static string DBFileName = "myDb.sqlite"; public static string DBpath; // D
public sealed partial class App : Application
{
// DB Name
public static string DBFileName = "myDb.sqlite";
public static string DBpath;
// DB Version
public static string DBVersionFilename = "myDb.version";
public static string DBVersionPath;
public static string DBVersion = "1.1.0";
public App()
{
this.InitializeComponent();
this.Suspending += this.OnSuspending;
ManageDB();
}
private async Task ManageDB()
{
if (!CheckDbExist().Result)
{
CreateDb();
}
else
{
if (CheckDbVersionUpdated().Result)
{
await DeleteDb();
CreateDb();
}
}
}
private async Task<bool> CheckDbExist()
{
try
{
StorageFile storageFile = await ApplicationData.Current.LocalFolder.GetFileAsync(DBFileName);
DBpath = storageFile.Path;
return true;
}
catch { }
return false;
}
private void CreateDb()
{
try
{
StorageFile storageFile = ApplicationData.Current.LocalFolder.CreateFileAsync(DBFileName, CreationCollisionOption.OpenIfExists).GetResults();
DBpath = storageFile.Path;
var dbconnection = new SQLiteAsyncConnection(DBpath, false);
dbconnection.CreateTableAsync<Article>();
//...
StorageFile file = ApplicationData.Current.LocalFolder.CreateFileAsync(DBVersionFilename, CreationCollisionOption.ReplaceExisting).GetResults();
FileIO.WriteTextAsync(file, DBVersion);
}
catch (Exception e)
{ }
}
private async Task<bool> DeleteDb()
{
try
{
StorageFile storageFile = ApplicationData.Current.LocalFolder.CreateFileAsync(DBFileName, CreationCollisionOption.OpenIfExists).GetResults();
await storageFile.DeleteAsync(StorageDeleteOption.PermanentDelete);
return true;
}
catch { }
return false;
}
private async Task<bool> CheckDbVersionUpdated()
{
try
{
string userDBVersion;
StorageFile file = await ApplicationData.Current.LocalFolder.GetFileAsync(DBVersionFilename);
userDBVersion = await FileIO.ReadTextAsync(file);
if (userDBVersion != DBVersion)
return true;
else
return false;
}
catch { }
return false;
}
}
公共密封部分类应用程序:应用程序
{
//数据库名
公共静态字符串DBFileName=“myDb.sqlite”;
公共静态字符串DBpath;
//数据库版本
公共静态字符串DBVersionFilename=“myDb.version”;
公共静态字符串DBVersionPath;
公共静态字符串DBVersion=“1.1.0”;
公共应用程序()
{
this.InitializeComponent();
this.Suspending+=this.OnSuspending;
ManageDB();
}
专用异步任务ManageDB()
{
如果(!CheckDbExist().Result)
{
CreateDb();
}
其他的
{
if(CheckDbVersionUpdated().Result)
{
等待DeleteDb();
CreateDb();
}
}
}
私有异步任务CheckDbExist()
{
尝试
{
StorageFile StorageFile=Wait ApplicationData.Current.LocalFolder.GetFileAsync(DBFileName);
DBpath=storageFile.Path;
返回true;
}
捕获{}
返回false;
}
私有void CreateDb()
{
尝试
{
StorageFile StorageFile=ApplicationData.Current.LocalFolder.CreateFileAsync(DBFileName,CreationCollisionOption.OpenIfExists)。GetResults();
DBpath=storageFile.Path;
var dbconnection=新的SQLiteAsyncConnection(DBpath,false);
dbconnection.CreateTableAsync();
//...
StorageFile file=ApplicationData.Current.LocalFolder.CreateFileAsync(DBVersionFilename,CreationCollisionOption.ReplaceExisting).GetResults();
WriteTextAsync(文件,DBVersion);
}
捕获(例外e)
{ }
}
专用异步任务DeleteDb()
{
尝试
{
StorageFile StorageFile=ApplicationData.Current.LocalFolder.CreateFileAsync(DBFileName,CreationCollisionOption.OpenIfExists)。GetResults();
等待storageFile.DeleteAsync(StorageDeleteOption.PermanentDelete);
返回true;
}
捕获{}
返回false;
}
私有异步任务CheckDbVersionUpdated()
{
尝试
{
字符串userDBVersion;
StorageFile file=Wait ApplicationData.Current.LocalFolder.GetFileAsync(DBVersionFilename);
userDBVersion=await FileIO.ReadTextAsync(文件);
if(userDBVersion!=DBVersion)
返回true;
其他的
返回false;
}
捕获{}
返回false;
}
}
CreateDB()
上有问题:
- 如果我使用断点一步一步地浏览这段代码,就不会有问题
- 但若我并没有放置断点,那个么在调用
vardbconnection=newsqliteasyncconnection(DBpath,false)后会遇到异常代码>:
private异步任务CreateDb()
{
尝试
{
StorageFile StorageFile=Wait ApplicationData.Current.LocalFolder.CreateFileAsync(DBFileName,CreationCollisionOption.OpenIfExists);
DBpath=storageFile.Path;
var dbconnection=新的SQLiteAsyncConnection(DBpath,false);
dbconnection.CreateTableAsync();
//...
StorageFile file=wait ApplicationData.Current.LocalFolder.CreateFileAsync(DBVersionFilename,CreationCollisionOption.ReplaceExisting);
WriteTextAsync(文件,DBVersion);
返回true;
}
捕获(例外e)
{ }
返回false;
}
你有什么解释吗
private async Task<bool> CreateDb()
{
try
{
StorageFile storageFile = await ApplicationData.Current.LocalFolder.CreateFileAsync(DBFileName, CreationCollisionOption.OpenIfExists);
DBpath = storageFile.Path;
var dbconnection = new SQLiteAsyncConnection(DBpath, false);
dbconnection.CreateTableAsync<Article>();
//...
StorageFile file = await ApplicationData.Current.LocalFolder.CreateFileAsync(DBVersionFilename, CreationCollisionOption.ReplaceExisting);
FileIO.WriteTextAsync(file, DBVersion);
return true;
}
catch (Exception e)
{ }
return false;
}