Winform control complex data binding common data sources (for example, dictionary) (multiple methods for assigning values to datasource controls such as ComboBox and datagridview)

Before getting started, let's take a look at the two forms of winform control data binding,Simple data binding and complex data binding.

1)Simple data binding

Simple data binding is to bind a property of a user control to a property of a Type instance. BIND as follows: Reference control. databindings. Add ("control property", instance object, "property name", true );

2)Complex Data Binding

Complex data binding involvesList-basedUser Controls (such as ComboBox, ListBox, errorprovider, and datagridview) bound to oneList of Data Objects.

Basically, complex data binding in Windows Forms allows binding to a list of data that supports the ilist interface. To bind a bindingsource component, You can bind it to a data list that supports the ienumerable interface.

For complex data binding, common data source types include (CodeComboBox is used as an example control ):

1) IlistInterface (including one-dimensional array, arraylist)

Example:

Private void initialcomboboxbylist ()

{

Arraylist list = new arraylist ();

For (INT I = 0; I <10; I ++)

{

List. Add (New dictionaryentry (I. tostring (), I. tostring () + "_ value "));

}

This. combobox1.displaymember = "key ";

This. combobox1.valuemember = "value ";

This. combobox1.datasource = List;

}

2)IlistsourceInterface (Datatable,Dataset)

Private void initialcomboboxbydatatable ()

{

Datatable dt = new datatable ();

Datacolumn DC1 = new datacolumn ("name ");

Datacolumn DC2 = new datacolumn ("value ");

 

DT. Columns. Add (DC1 );

DT. Columns. Add (DC2 );

 

For (INT I = 1; I <= 10; I ++)

{

Datarow DR = DT. newrow ();

Dr [0] = I;

Dr [1] = I + "--" + "hello ";

DT. Rows. Add (DR );

}

 

This. combobox1.displaymember = "name ";

This. combobox1.valuemember = "value ";

This. combobox1.datasource = DT;

}

3)IbindinglistInterface (suchBindinglistClass)

4)IbindinglistviewInterface (suchBindingsourceClass)

Example:

Private void initialcomboboxbybindingsource ()

{

Dictionary <string, string> DIC = new bindingsource <string, string> ();

For (INT I = 0; I <10; I ++)

{

Dic. Add (I. tostring (), I. tostring () + "_ Hello ");

This. combobox1.displaymember = "key ";

This. combobox1.valuemember = "value ";

This. combobox1.datasource = new bindingsource (DIC, null );

}

}

Note the aboveProgramThe datasource attribute value of bindingsource is a dictionary instance. If you use DIC to assign a value to ComboBox directly, the program reports an error because dictionary <> does not implement the ilist or ilistsource interface, however, you can bind a dictionary to bindingsource. For more details about bindingsource, refer to the following link:

Http://msdn.microsoft.com/zh-cn/library/system.windows.forms.bindingsource (vs.80). aspx

Let's look at the following bindingsource example:

Private void initialcomboboxbyobject ()

{

This. combobox1.displaymember = "name ";

This. combobox1.valuemember = "value ";

This. combobox1.datasource = new bindingsource (New dictionaryentry ("test", "test_value"), null );

}

In the code above, the datasource of bindingsource is a schema type dictionaryentry. Similarly, the dictionaryentry cannot be directly assigned to the datasource of ComboBox, but it can still be indirectly implemented through bindingsource.

This is because:

BindingsourceIt can be used as a strongly typed data source. The data source type is fixed by one of the following mechanisms:

· Use the add method to add an itemBindingsourceComponent.

· Set the datasource attribute toList,Single ObjectOrType. (These three do not have to implement ilist or ilistsource)

both of these mechanisms create a list of strong types. bindingsource supports simple data binding and complex data binding indicated by its datasource and datamember attributes.