Data Binding and analysis of several methods and usage of Container. DataItem

Flexible Use of Data Binding
Bind to simple attributes: <% # UserName %>
Bind to collection: <asp: ListBox id = "ListBox1" datasource = '<% # myArray %> 'runat = "server">
Binding to expression: <% #(class1.property1. ToString () + "," + class1.property2. ToString () %>
Return Value bound to the method: <% # GetSafestring (str) %>
Bind to Hashtable: <% # (DictionaryEntry) Container. DataItem). Key %>
Bind to ArrayList: <% # Container. DataItem %>

If an object is put in the array, you may need to convert the object before binding it, for example:
<% # (Object Type) Container. DataItem). Attribute %>

Bind to DataView, able, DataSet:
<% # (DataRowView) Container. DataItem) ["field name"] %> or
<% # (DataRowView) Container. DataItem). Rows [0] ["field name"] %>
To Format:
<% # String. Format ("Format", (DataRowView) Container. DataItem) ["field name"]) %>
<% # DataBinder. Eval (Container. DataItem, "field name", "format") %>

Bind to DataReader:
<% # (IDataReader) Container. DataItem). Field name %>

Of course, the Eval method of the DataBinder class is generally used for convenience. However, it is less efficient to bind a large amount of data at the same time.

This program is often used when binding data: <% # DataBinder. eval (Container. dataItem, "xxxx") %> or <% # DataBinder. eval (Container, "DataItem. xxxx ") %>
Today I learned another method, and Microsoft also said that this method is more efficient than the above two methods.

<% # (DataRowView) Container. DataItem) ["xxxx"] %>

Very useful, so that you can do a lot of things on the front-end page.

Remember to import the namespace System. Data on the front-end page. Otherwise, an error message is generated.

<% @ Import namespace = "System. Data" %>

This usage is actually the same as <% # (DictionaryEntry) Container. DataItem). Key %>.

When binding to DataSet or able:

<% # (System. Data. DataRowView) Container. DataItem) ["field name"] %>
<% # (System. Data. DataRowView) Container. DataItem) [Index] %>

When bound to DataReader:
<% # (System. Data. Common. DbDataRecord) Container. DataItem) [Index] %>
<% # (System. Data. Common. DbDataRecord) Container. DataItem) ["field name"] %>

The key is the Container, which is mysterious. Its namespace is System. ComponentModel. I need to further understand it.

Beginner. NET, now reading the DataGrid Control, when ItemTemplate displays data,
What is the difference between DataBinder. Eval (Container. DataItem, "Name") and Container. DataItem ("Name?

DataBinder is System. A static class in the Web, which provides the Eval method to simplify writing data binding expressions. However, it uses Reflection and other overhead methods to achieve ease of use, therefore, its performance is not the best. The Container is not a static object or method at all. It is ASP. NET page compiler local variables declared in the Data Binding event handler, its type is the data container type of controls that can be bound to data (for example, the data binding container inside the Repeater is called RepeaterItem). In these container classes, DataItem attributes are basically available, therefore, you can write Container. dataItem, which returns the data item from the data source you are bound. If your data source is DataTable, the Data Type of this data item is actually DataRowView.

From jarin's column