dispose

问题 I have this: Bitmap bmp = new Bitmap(image); //image processing bmp.Save(path + fileName); and I want to know if I need to call bmp.Dispose() after this code. Thanks in advance. 回答1: I would use using block and Path.Combine using(var bmp = new Bitmap(image)) { // image processing bmp.Save(Path.Combine(path ,fileName)); } 回答2: Yes. Better yet, you could wrap your bmp in a using block, this will take care of the disposal for you using(var bmp = new Bitmap(image)) { bmp.Save(...); } Save's sole

问题 I have a web service that is quite heavy on database access. It works fine in test, but as soon as I put it in production and ramp up the load it starts churning out errors that are raised when something calls a method in the DataContext. The error is normally one of these: Object reference not set to an instance of an object Cannot access a disposed object. Object name: 'DataContext accessed after Dispose.'. but not always. Any single web service requests can result as many as 10 or 15

问题 Take the following example... Using cn As New SqlConnection(ConnectionString) Try Dim cmd As SqlCommand = New SqlCommand With cmd .Connection = cn .Connection.Open() .CommandText = "dbo.GetCustomerByID" .CommandType = CommandType.StoredProcedure .Parameters.Add("@CustomerID", SqlDbType.Int, 4) .Parameters("@CustomerID").Value = CustomerID End With da = New SqlDataAdapter(cmd) da.Fill(ds, "Customer") Catch ex As Exception End Try End Using From my research today is sounds as though this is

问题 I'm currently learning how to use Autofac, and I'm stuck with disposing IDisposable objects deterministically. Let me first present the situation before I'll state my problem. Starting position: Let's say my object model is defined through the following interfaces: interface IApple : IDisposable { void Consume(); } interface IHorse { void Eat(IApple apple); // is supposed to call apple.Consume() } interface IHorseKeeper { void FeedHorse(); // is supposed to call horse.Eat(apple) // where

问题 Although I have been coding for some time, I'm really just barely into what I would call an intermediate level coder. So I understand the principle of dispose(), which is to release memory reserved for variables and/or resources. I have also found sometimes using EF I have to dispose() in order for other operations to work properly. What I don't understand is just exactly what requires a release, when to employ dispose(). For example, we don't dispose variables like string, integer or

问题 In my current project there is a Form class which looks like this: public partial class FormMain : Form { System.Timers.Timer timer; Point previousLocation; double distance; public FormMain() { InitializeComponent(); distance = 0; timer = new System.Timers.Timer(50); timer.AutoReset = true; timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed); timer.Start(); } private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e) { if (previousLocation != null) { // some

问题 I can never remember all the rules for implementing the IDisposable interface, so I tried to come up with a base class that takes care of all of this and makes IDisposable easy to implement. I just wanted to hear your opinion if this implementation is ok as it is or whether you see something I could improve. The user of this base class is supposed to derive from it and then implement the two abstract methods ReleaseManagedResources() and ReleaseUnmanagedResources() . So here is the code:

问题 I am trying to dispose XmlWriter object: try { [System.Xml.XmlWriter] $writer = [System.Xml.XmlWriter]::Create('c:\some.xml') } finally { $writer.Dispose() } Error: Method invocation failed because [System.Xml.XmlWellFormedWriter] doesn't contain a method named 'Dispose'. On the other side: $writer -is [IDisposable] # True What should I do? 回答1: Dispose is protected on System.Xml.XmlWriter . You should use Close instead. $writer.Close 回答2: Here is an alternative approach: (get-interface $obj

问题 I have this code: Dim xx as image xx = image.fromfile(Fileloc) picturebox.image = xx And i can't delete the file even though I've loaded it into a picture box. If I add this line: xx.dispose the picture box becomes a big red X. I only want to delete the images when my application is closing (they are temp files). So shall I just dispose them before I delete them? 回答1: Don't use Image.FromFile , it keeps the file open. From MSDN : The file remains locked until the Image is disposed. Do that

问题 I have this code: Dim xx as image xx = image.fromfile(Fileloc) picturebox.image = xx And i can't delete the file even though I've loaded it into a picture box. If I add this line: xx.dispose the picture box becomes a big red X. I only want to delete the images when my application is closing (they are temp files). So shall I just dispose them before I delete them? 回答1: Don't use Image.FromFile , it keeps the file open. From MSDN : The file remains locked until the Image is disposed. Do that