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  • How can I bind events to strongly typed datasets of different types?

    My application contains several forms which consist of a strongly typed datagridview, a strongly typed bindingsource, and a strongly typed table adapter. I am using some code in each form to update the database whenever the user leaves the current row, shifts focus away from the datagrid or the form, or closes the form. This code is the same in each case, so I want to make a subclass of form, from which all of these forms can inherit. But the strongly typed data objects all inherit from component, which doesn't expose the events I want to bind to or the methods I want to invoke. The only way I can see of gaining access to the events is to use: Type(string Name).GetEvent(string EventName).AddEventHandler(object Target,Delegate Handler) Similarly, I want to call the Update method of the strongly typed table adapter, and am using Type(string Name).GetMethod(String name, Type[] params).Invoke(object target, object[] params). It works ok, but it seems very heavy handed. Is there a better way? Here is my code for the main class: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; using System.ComponentModel; namespace MyApplication { public class AutoSaveDataGridForm: Form { private DataRow PreviousRow; public Component Adapter { private get; set; } private Component dataGridView; public Component DataGridView { private get { return dataGridView; } set { dataGridView = value; Type t = dataGridView.GetType(); t.GetEvent("Leave").AddEventHandler(dataGridView, new EventHandler(DataGridView_Leave)); } } private Component bindingSource; public Component BindingSource { private get { return bindingSource; } set { bindingSource = value; Type t = bindingSource.GetType(); t.GetEvent("PositionChanged").AddEventHandler(bindingSource, new EventHandler(BindingSource_PositionChanged)); } } protected void Save() { if (PreviousRow != null && PreviousRow.RowState != DataRowState.Unchanged) { Type t = Adapter.GetType(); t.GetMethod("Update", new Type[] { typeof(DataRow[]) }).Invoke(Adapter, new object[] { new DataRow[] { PreviousRow } }); } } private void BindingSource_PositionChanged(object sender, EventArgs e) { BindingSource bindingSource = sender as BindingSource; DataRowView CurrentRowView = bindingSource.Current as DataRowView; DataRow CurrentRow = CurrentRowView.Row; if (PreviousRow != null && PreviousRow != CurrentRow) { Save(); } PreviousRow = CurrentRow; } private void InitializeComponent() { this.SuspendLayout(); // // AutoSaveDataGridForm // this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.AutoSaveDataGridForm_FormClosed); this.Leave += new System.EventHandler(this.AutoSaveDataGridForm_Leave); this.ResumeLayout(false); } private void DataGridView_Leave(object sender, EventArgs e) { Save(); } private void AutoSaveDataGridForm_FormClosed(object sender, FormClosedEventArgs e) { Save(); } private void AutoSaveDataGridForm_Leave(object sender, EventArgs e) { Save(); } } } And here is a (partial) form which implements it: public partial class FileTypesInherited :AutoSaveDataGridForm { public FileTypesInherited() { InitializeComponent(); } private void FileTypesInherited_Load(object sender, EventArgs e) { // TODO: This line of code loads data into the 'sharedFoldersInformationV2DataSet.tblFileTypes' table. You can move, or remove it, as needed. this.tblFileTypesTableAdapter.Fill(this.sharedFoldersInformationV2DataSet.tblFileTypes); this.BindingSource = tblFileTypesBindingSource; this.Adapter = tblFileTypesTableAdapter; this.DataGridView = tblFileTypesDataGridView; } }

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  • How to instanciate a class when its property members are not of primitive types?

    - by Richard77
    Hello, 1) Let's say I've a class MyDataInfo public class MyDataInfo { public int MyDataInfoID { get; set; } public string Name { get; set; } } For the purpose of the fuctionality I'm after, I've created another class (MyData) whose property members are of MyDataInfo type. 2) Here's myData public class MyData { public MyDataInfo Prop1 { get; set; } public MyDataInfo Prop2 { get; set; } } 3) And, here's my action method public ActionResult MyAction() { MyData myObject = new MyData(); return View(myObject); } 4) Finally, this in my View template (which is strongly typed and inherits from MyData) <% = Html.Encode (Model.Prop1.Name)%> <% = Html.Encode (Model.Prop2.Name)%> Unfortunately, I got an error "Object not set to an instance of an object." Am I missing something or is there a different way of obtaining the same result? Thanks for helping

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  • Is there a way to achieve covariance of generic types in C# 3.0?

    - by nullDev
    This has been introduced in C# 4.0, but is there a way to achieve this in c# 3.0? For e.g., consider the following code: class Base { } class Derived1 : Base { } class Derived2 : Base { } class User<T> where T : Base { } class User1 : User<Derived1> { } Now, I would like to have a list of User<T>, in which I can store User<Derived1> as well as User<Derived2>, but the following code fails to compile in C# 3.0: List<User<Base>> users = new List<User<Base>>(); users.Add(new User1()); Any ideas?

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  • How do I apply css for textboxes only but not for all the <input> types like CheckBoxes, etc.?

    - by George
    If all browsers supported attribute selectors, we could easily do the following: input[type='text'] { font:bold 0.8em 'courier new',courier,monospace; } input[type='radio'] { margin:0 20px; } input[type='checkbox'] { border:2px solid red; But I don't think all IE versions of ^ and greater support this. I think I'd like to avoid skins. Not sure why, other than I tried them and I recall having a negative experience. It was probably my lack of knowledge. Are there any issues in using and CSS, external or otherwise? What's the best way to handle this? Currently I am assigning separate classes to each control type.

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  • How to deploy a number of disparate project types?

    - by niteice
    This question is similar to http://stackoverflow.com/questions/1900269/whats-the-best-way-to-deploy-an-executable-process-on-a-web-server. The situation is this: I'm developing a product that needs to be deployed to a web server. It consists of 4 website projects, a background service, a couple of command-line tools, and two assemblies shared by all of these components. Now, I also happen to administer the server that this product will be deployed on. So I'm familiar with everything that may need to be done to perform an update: Copy website files Replace the service binary Install updated components in the GAC Configure IIS Update database schema After some research it seems that, to reduce deployment time and to be able to let the other sysadmins handle deployment, I want to deploy all of these as an MSI, except that I don't know a thing about installers. I know VS can generate web deployment projects, but where do I go from there? Being able to simply click Next a few times on an installer is my goal for deploying updates. It would also be nice to modularize it, so for example, I could distribute the four websites among multiple servers and have everything appear as individual components in the installer, and as one entity in Add/Remove Programs. Is all of this too much to ask in a single package?

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  • How does the iPhone SDK Core Data system store date types to sqlite?

    - by Andrew Arrow
    I used core data to do this: NSManagedObjectContext *m = [self managedObjectContext]; Foo *f = (Foo *)[NSEntityDescription insertNewObjectForEntityForName:@"Foo" inManagedObjectContext:m]; f.created_at = [NSDate date]; [m insertObject:f]; NSError *error; [m save:&error]; Where the created_at field is defined as type "Date" in the xcdatamodel. When I export the sql from the sqlite database it created, created_at is defined as type "timestamp" and the values look like: 290902422.72624 Nine digits before the . and then some fraction. What is this format? It's not epoch time and it's not julianday format. Epoch would be: 1269280338.81213 julianday would be: 2455278.236746875 (notice only 7 digits before the . not 9 like I have) How can I convert a number like 290902422.72624 to epoch time? Thanks!

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  • Is there an easier way to typecast with unknown types?

    - by Adam S
    Hi all. I am writing a function to recurse my XAML and add all the controls to a hashtable, with their names being the keys. Unfortunately it seems like I have to go through and list every possible type: void Recurse_Controls(object start) { string start_type = start.GetType().ToString(); if (start_type == "StackPanel") { ControlsByName.Add(((StackPanel)start).Name, start); foreach (object item in ((StackPanel)start).Children) { Recurse_Controls(item); } } if (start_type == "Grid") { ControlsByName.Add(((Grid)start).Name, start); foreach (object item in ((Grid)start).Children) { Recurse_Controls(item); } } } Is there a simpler way of doing this?

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  • Does `throw` cause stack variables (full types) to be freed from memory in C++?

    - by nbolton
    I'm pondering a question on Brainbench. I actually realised that I could answer my question easily by compiling the code, but it's an interesting question nonetheless, so I'll ask the question anyway and answer it myself shortly. Take a look at this snippet: The question considers what happens when we throw from a destructor (which causes terminate() to be called). It's become clear to me by asking the question that the memory is indeed freed and the destructor is called, but, is this before or after throw is called from foo? Perhaps the issue here is that throw is used while the stack is unwinding that is the problem... Actually this is slightly confusing.

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  • XNA Class Design with Structs as Properties and issues because they are value types and not referenc

    - by Nate Bross
    I'm wondering how you'd recommend designin a class, given the fact that XNA Framework uses Struct all over the place? For example, a spite class, which may require a Vector2 and a Rectangle (both defined as Struct) to be accessed outside of the class. The issue come in when you try to write code like this: class Item { public Vetor2 Position {get; set;} public Item() { Position = new Vector2(5,5); } } Item i = new Item(); i.Positon.X = 20; // fails with error 'Cannot modify the return value of Item because it is not a variable.' // you must write code like this var pos = i.Position; pos.X++; i.Position = pos; The second option compiles and works, but it is just butt ugly. Is there a better way?

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  • Declare 2 types inside using statement gives compile error?

    - by citronas
    I want to use this line of code: using (ADataContext _dc = new ADataContext(ConnectionString), BDataContext _dc2 = new BrDataContext(ConnectionString)){ // ...} This gives a compile error: Cannot use more than one type in a for, using, fixed or declartion statement. I thought this was possible? MSDN says it is: http://msdn.microsoft.com/en-us/library/yh598w02%28VS.80%29.aspx In the MSDN sample code Font is used, which is class and thereby a reference type as well as my two DataContext classes. What went wrong here? How does my attempt differ from the MSDN sample?

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  • How does Python differentiate between the different data types?

    - by wrongusername
    Sorry if this is quite noobish to you, but I'm just starting out to learn Python after learning C++ & Java, and I am wondering how in the world I could just declare variables like id = 0 and name = 'John' without any int's or string's in front! I figured out that perhaps it's because there are no ''s in a number, but how would Python figure that out in something like def increase(first, second) instead of something like int increase(int first, int second) in C++?!

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  • Is there a way to achieve covariance of generic types in C# 3.5?

    - by nullDev
    This has been introduced in C# 4.0, but is there a way to achieve this in c# 3.5? For e.g., consider the following code: class Base { } class Derived1 : Base { } class Derived2 : Base { } class User<T> where T : Base { } class User1 : User<Derived1> { } Now, I would like to have a list of User<T>, in which I can store User<Derived1> as well as User<Derived2>, but the following code fails to compile in C# 3.5: List<User<Base>> users = new List<User<Base>>(); users.Add(new User1()); Any ideas?

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  • does mysql stored procedures support data types like array, hash,etc?

    - by Yang
    i am creating a mysql function which takes in a varchar and change it to a int based on a mapping table. select name, convert_to_code(country) from users where sex = 'male' here, the convert_to_code() function takes in a country name (e.g. Japan, Finland..) and change it to country code which is an integer (e.g. 1001, 2310..) based on a mapping table called country_maping like below: country_name (varchar) | country_code (int) Japan | 1001 Finland | 2310 Canada | 8756 currently, the stored function need to select country_code from country_mapping where country_name = country_name and return the query result. is that possible to create a hash data struct in SP to optimize the process so that it will not need to perform the query for each row matches the where clause. thanks in advance!

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  • SQLAlchemy introspection of ORM classes/objects

    - by Adam Batkin
    I am looking for a way to introspect SQLAlchemy ORM classes/entities to determine the types and other constraints (like maximum lengths) of an entity's properties. For example, if I have a declarative class: class User(Base): __tablename__ = "USER_TABLE" id = sa.Column(sa.types.Integer, primary_key=True) fullname = sa.Column(sa.types.String(100)) username = sa.Column(sa.types.String(20), nullable=False) password = sa.Column(sa.types.String(20), nullable=False) created_timestamp = sa.Column(sa.types.DateTime, nullable=False) I would want to be able to find out that the 'fullname' field should be a String with a maximum length of 100, and is nullable. And the 'created_timestamp' field is a DateTime and is not nullable.

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  • How to replace all id attributes of a child collection of complex types using jQuery in ASP.net MVC

    - by TJB
    Here's my situation: I'm writing an ASP.net MVC 1 website and I have a create/edit form that uses the default model binding to parse the form into a strongly typed complex object. The object I'm posting has a child collection of another complex type and the way I format my id's for the model binder is as follows: <div class="childContainer" > <!-- There's one of these for each property for each child collection item --> <%= Html.TextBox("ChildCollectionName[0].ChildPropertyName", /* blah blah */ ) %> <%= Html.TextBox("ChildCollectionName[0].OtherChildPropertyName", /* blah blah */ ) %> <!-- ... --> </div> This gets rendered as <div class="childContainer" > <input id="ChildCollectionName[0]_ChildPropertyName" ... /> <input id="ChildCollectionName[0]_OtherChildPropertyName" ... /> ... </div> <div class="childContainer" > <input id="ChildCollectionName[1]_ChildPropertyName" ... /> <input id="ChildCollectionName[1]_OtherChildPropertyName" ... /> ... </div> For each entry in the chlid collection. This collection is dynamically created in the form using jQuery, so entries can be added, removed etc. and whenever there's an operation on the collection I need to update the indexes so that it's bound correctly on the server side. What's the best way to replace all the html input id's when I'm updating the index within the child e.g. replace all [*] -- [N] where N is the correct index. using jQuery / JavaScript ? I have something coded now, but its buggy and I think there is a simpler solution. Also, if you have an easier way to identify the child collection I'll take any advice on that as well. Thanx!

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  • Can a Generic Method handle both Reference and Nullable Value types?

    - by Adam Lassek
    I have a series of Extension methods to help with null-checking on IDataRecord objects, which I'm currently implementing like this: public static int? GetNullableInt32(this IDataRecord dr, int ordinal) { int? nullInt = null; return dr.IsDBNull(ordinal) ? nullInt : dr.GetInt32(ordinal); } public static int? GetNullableInt32(this IDataRecord dr, string fieldname) { int ordinal = dr.GetOrdinal(fieldname); return dr.GetNullableInt32(ordinal); } and so on, for each type I need to deal with. I'd like to reimplement these as a generic method, partly to reduce redundancy and partly to learn how to write generic methods in general. I've written this: public static Nullable<T> GetNullable<T>(this IDataRecord dr, int ordinal) { Nullable<T> nullValue = null; return dr.IsDBNull(ordinal) ? nullValue : (Nullable<T>) dr.GetValue(ordinal); } which works as long as T is a value type, but if T is a reference type it won't. This method would need to return either a Nullable type if T is a value type, and default(T) otherwise. How would I implement this behavior?

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  • How do polymorphic inline caches work with mutable types?

    - by kingkilr
    A polymorphic inline cache works by caching the actual method by the type of the object, in order to avoid the expensive lookup procedures (usually a hashtable lookup). How does one handle the type comparison if the type objects are mutable (i.e. the method might be monkey patched into something different at run time). The one idea I've come up with would be a "class counter" that gets incremented each time a method is adjusted, however this seems like it would be exceptionally expensive in a heavily monkey patched environ since it would kill all the PICs for that class, even if the methods for them weren't altered. I'm sure there must be a good solution to this, as this issue is directly applicable to Javascript and AFAIK all 3 of the big JS VMs have PICs (wow acronym ahoy).

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  • What's the difference between these two calls to a function taking a collection of structural types?

    - by James Moore
    Why does the call to fn(Iterator("foo") compile, but the call to fn(fooIterator) fail with an error "type mismatch; found : Iterator[java.lang.String] required: scala.Iterator[com.banshee.Qx.HasLength]" object Qx { type HasLength = {def length: Int} def fn(xs: Iterator[HasLength]) = 3 var tn = fn(Iterator("foo")) var fooIterator = Iterator("foo") var tnFails = fn(fooIterator) //doesn't compile } Aren't they the same thing?

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