asp+| note 8). Customization of data access
In addition to the DataGrid, there are DataList and Repeater, which can be more flexible to use, but you need to provide templates,
Using the control templates
They also have attribute datasource, which can be assigned to a ICollection object, the ItemTemplate control specifies each record
The appearance of showing, example:
<asp:repeater id= "MyRepeater" runat= "Server" >
<template name= "ItemTemplate" >
<%# DataBinder.Eval (Container.DataItem, "name")%>
</template>
</ASP:Repeater>
Where: Container represents the first control containing System.Web.UI.INamingContainer outside the control, in this case
is a system.web.ui.webcontrols,repeateritem that contains a DataItem attribute.
In addition, you can also use HeaderTemplate and FooterTemplate.
DataList has more control, such as his repeatercoumns attribute can specify a line to repeat several times, repeatdirection
Specifies the direction.
Inserting the LinkButton control can cause a select event, in which DataList can be set to specify the event handler OnSelectedIndexChanged property.
Cases:
<asp:datalist id= "DL" onselectedindexchanged= "Dl_select" >
<asp:linkbutton command= "Select" runat= "Server" >
<% #DataBinder. Eval (Container.DataItem.) Title ")%>
</asp:LinkButton>
......
<script language= "C #" runat= "Server" >
void Dl_select (Object Sencer,eventargs E) {
......
}
</script>
Note that there may be multiple events, such as Edit/update/cancel, so you can use a uniform onitemcommand to handle
Judge by command what exactly is the event. Cases:
void Dl_select (Object Src,datalistcommandeventargs E) {
String command= ((LinkButton) e.commandsource). Text;
Switch (command)
{case "discuss": ... break;
Case "ratings": ... break;
}
}
<asp:linkbutton command= "ratings" runat= "Server" >
View ratings
</asp:LinkButton>
Even better, DataList can also support edit and select Templates!!
Cases:
void Mydatalist_edit (Object Sender,datalistcommandeventargs E) {
Mydatalist.edititemindex = (int) E.item,itemindex;
Set who is selected for editing
.../re-fix
}
void Mydatalist_update (Object Sender,datalistcommandeventargs E) {
String Price = ((HtmlInputText) E.item.findcontrol ("Edit_price")). Value;
......
Mydatalist.edititemindex=-1;
}
......
<template name= "EditItemTemplate" >
......
<b>price:</b><input id= "Edit_price" type= "text" >
.
.
.
This can be easily used in the system background maintenance.
Problem, the example in the template has just one control, so FindControls works, but what if there are multiple?
You can traverse through the DataList items collection, such as:
for (int i=0;i<mydatalist.items.count;i++)
String ischecked = ((CheckBox) mydatalist.items[i]. FindControls ("Save")). Checked. ToString ();
<template name= "ItemTemplate" >
<asp:checkbox id= "Save" runat=server>
</template>
9). Commercial controls
。 Application Bin directory
In the ASP components need to register with regsvr32, not convenient remote management, asp+ only need to put in the application of the/bin directory.
<%import namespace= "HelloWorld"%> introduce namespaces, config files to specify which controls to use, for example:
<configuration>
<compilation>
<assemblies>
<add assembly= "System.Data"/>
<add assembly= "System.Web.Services"/>
<add assembly= "System.Drawing"/>
<add assembly= "*"/>
</assemblies>
</compilation>
</configuration>
Of these, the first three are global and the last one is under the bin directory.
10). Write Control
Slightly.
Note that you need to derive from Controls (System.Web.UI.Controls)
11). WebForms Control Reference
Two major categories,
One is System.Web.UI.HtmlControls, which starts with HTML and is displayed on a Web page.
The second is System.Web.UI.WebControls, attached, such as the DataGrid.
Concrete slightly.
12). WebForms An expression reference
<%%> code block,<%=%> also supported.
<script runat= "Server" >
server controls with: <asp:lable ... runat= "Server" >
HTML server controls with: <span id= "message" runat= "Server" >
Data help: <%#%>
Objects: <ob
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