out-parameters

Suppose I have: public class Bob { public int Value { get; set; } } I want to pass the Value member as an out parameter like Int32.TryParse("123", out bob.Value); but I get a compilation error, "'out' argument is not classified as a variable." Is there any way to achieve this, or am I going to have to extract a variable, à la: int value; Int32.TryParse("123", out value); bob.Value = value; You'd have to explicitly use a field and "normal" property instead of an auto-implemented property: public class Bob { private int value; public int Value { get { return value; } set { this.value = value; }

I want expose WebClient.DownloadDataInternal method like below: [ComVisible(true)] public class MyWebClient : WebClient { private MethodInfo _DownloadDataInternal; public MyWebClient() { _DownloadDataInternal = typeof(WebClient).GetMethod("DownloadDataInternal", BindingFlags.NonPublic | BindingFlags.Instance); } public byte[] DownloadDataInternal(Uri address, out WebRequest request) { _DownloadDataInternal.Invoke(this, new object[] { address, out request }); } } WebClient.DownloadDataInternal has a out parameter, I don't know how to invoke it. Help! public class MyWebClient : WebClient {

Does VB.NET have a direct equivalent to C# out function parameters, where the variable passed into a function does not need to be initialised? No, there is no equivalent of the out keyword in VB. However, VB does automatically initialise all local variables in a method, so you can use ByRef without needing to explicitly initialise the variable first. Example: Sub Main() Dim y As Integer Test(y) End Sub Sub Test(ByRef x As Integer) x = 42 End Sub (If you examine code in the framework (for example Double.TryParse ), you may see the <OutAttribute> added to parameters, but that only makes a

I'm trying to understand different ways of getting table data from Oracle stored procedures / functions using JDBC. The six ways are the following ones: procedure returning a schema-level table type as an OUT parameter procedure returning a package-level table type as an OUT parameter procedure returning a package-level cursor type as an OUT parameter function returning a schema-level table type function returning a package-level table type function returning a package-level cursor type Here are some examples in PL/SQL: -- schema-level table type CREATE TYPE t_type AS OBJECT (val VARCHAR(4));

Take the following: class A {} class B : A {} class C { C() { var b = new B(); Foo(b); Foo2(ref b); // <= compile-time error: // "The 'ref' argument doesn't match the parameter type" } void Foo(A a) {} void Foo2(ref A a) {} } Why does the above compile-time error occur? This happens with both ref and out arguments. Eric Lippert ============= UPDATE: I used this answer as the basis for this blog entry: Why do ref and out parameters not allow type variation? See the blog page for more commentary on this issue. Thanks for the great question. ============= Let's suppose you have classes Animal ,