Meaning of <%%><%#%><%=%> represented in C #

1.<%%>

Server code can be executed, in layman's words can be written like the background code, such as:

1 <%2         int2; 3         int 3 ; 4         int C = a + b; 5         Response.Write (c); 6 %>

2.<%=%>
The expression for a service-side language can be a method with a return value, but the return value cannot be too large, note that there must be a return value . It can actually be seen as a binding.

Aspx.cs Code:

1  Public string  DISPLAYSTR ()// Note that there must be a return value here, or a run-time error of 2{3     return will occur " bbbb " ; 4 }

ASPX code:

1 <label id="label1"><%=displaystr ()%></label><br/> 2 <label id="label2" runat="server" ><%= Displaystr ()%></label>

3.<%#%>
This format is unique to ASP. XML, which is the syntax for control data binding. can only be used in data-bound controls. For example

3.1

Aspx.cs Code:

1 protected stringtext;2 protected voidPage_Load (Objectsender, EventArgs e)3 {4       if(!Page.IsPostBack)5       {6              This. Text ="aaaaaaaaaaaaa";7              This. Textbox1.databind ();//or this.              DataBind (); 8        }9}

ASPX code:

1<div>2Server Control:<asp:textbox id="TextBox1"runat="Server"text="<% #text%>"&GT;&LT;/ASP:TEXTBOX&GT;&LT;BR/><!--Server control-->3Client Control:<input type="text"Id="TextBox2"Value="<% #text%>"/><!--Client control-->4</div>

3.2 <% #Eval ("data column")%>

Primarily used to bind data columns that need to be changed, such as
Aspx.cs Code:

If the field value is 0 returns the male, otherwise returns the female

1  Public ObjectChangesex (Objectobj)2         {3             if(obj. ToString () = ="0")4             {5                 return "male";6             }7             Else 8             {9                 return "female";Ten             } One}

ASPX code:

Bind the Gender field to this binding to this, the gender value is variable

1 <% #ChangeSex (Eval (" gender "))%>=

3.3 <% #Bind ("data column")%>

A data column binding that is common in the GridView that does not require processing.
4 <%$%>

A common use of expressions is to set the connection string properties of a control (such as a SqlDataSource control) based on the value of the connection string stored in the Web. config file. For example, you might have the following SqlDataSource control that contains the connection string properties:

1 <asp:sqldatasource id="SqlDataSource1" runat="server " 2      selectcommand="select * FROM [Test]"3      connectionstring="  <%$ connectionstrings:testconnectionstring%>">4  </asp: Sqldatasource>

5. <%@%>
This syntax is primarily used for import, and the most familiar scenario is the one at the top of the ASPX page, such as the following code:

<% @Page .......%>

The line code is meant to define page-specific properties that are used by the ASP and the compiler, and can only be included in the ASPX page.

Meaning of <%%><%#%><%=%> represented in C #