Introduction to C# Web Applications Classic Notes (Volume 2)

Read the settings in Web.config

Conn = new SqlConnection(ConfigurationSettings.AppSettings[“cnFriends.ConnectString”]);

 <appSettings> 
    <!--   User application and configured property settings go here.--> 
    <!--   Example: <add key="settingName" value="settingValue"/> --> 
<add key="cnFriends.ConnectionString" value="data source=(local)\NetSdk;initial catalog=FriendsData;user id=sa" />  </appSettings>

Several namespaces

When using DataSet, use using system.Data.SqlClient

When When configuring Web.config, use using system.Configuration

This reminds me of when I was learning C language in my freshman year

bool visible 
btnSearch.Text = visible? “New Search” : “Search” ;

This is also pretty good

dsResult.tables[“Users”].rows.count 
Conver.Tonint32(ConfigurationSettings.AppSettings[“Cokuale.number”]);

Ruthless 1: Use Session to save the results and bind them

Session[“Search”] = dsResults; 
dsResults = (DataSet) Session[“Search”];

grdResults.DataBind();
In fact, Session, Application, etc. are stored in object type, so they must be displayed in the end. Type conversion type
By the way, use null to judge whether a string type value is obtained.

Quehen 2: Select rows from DataTable

DataRow[] rows = dsResults.Tables[“Users”].Select(filter); 
dsResults = dsResults.Clone(); 
foreach(DataRow row in rows) 
{ 
         dsResults.Tables[“Tables”].ImportRow(row); 
}

Get a control on the webForm

ImageButton img = (ImageButton)e.Item.FindControl(“Selectbutton”)

Jump:

Server.Transfer(“Caoxicao.aspx”);

Add js script (Attributes attribute) to the server control

imgShow.Attributes.Add(“onclick”,”document.getElementById(‘tbPrefs').style.display = ‘block';”);

Then (Style attribute),

img.Style.Add(“Cursor”,'Pointer');

Color related:

ColorConvert cv = new ColorConvert(); 
Color selected = Color.Empty; 
Selected = (olor)cv.ConvertFromString(White);

Add Cookie

Response.Cookies.Add(new HttpCookie(“backColor”,r))

My Favorite----User Control

Using FriendsReunion.Controls; 
Protectd override void Oninit(EventArgs e) 
{ 
         FriendsFooter _footer = (FriendsFooter)LoadControl(Request.ApplicationPath+”/Controls/ FriendsFooter.aspx”); 
         SubHeader _subHeader = new SubHeader(); 
} 
Page.Contros.AddAt(0,_footer); 
Page.Contros.AddAt(0,_subHeader); 
base.OnInit(e); 
}

New Html Control Instance

HtmlGenericControl p = new HtmlGenericControl(“p”); 
p.Style.Add(“background-color”,bg);

Use this Classes can represent HTML server control tags that are not directly represented by .NET Framework classes, such as 45a2772a6b6107b401db3c9b82c049c2, e388a4556c0f65e1904146cc1a846bee, 6c04bd5ca3fcae76e30b72ad730ca86d and 240cb830ca84ebaabbd07850110b414d

Return DataSet

Public DataSet Contact() 
{ 
         String sql = “@ Select * from … …”; 
         DataSet requests = new DataSet(); 
         New SqlDtaAdapter (sql,conn).Fill(requests); 
         //return requests.GetXml(); 
                   Return requests; 
}

Receive: (when the return value is a data set in Xml format)

DataSet results = new DataSet(); 
Results.ReadXml(new StringReader(fi.ContactRequest(userid)));

When using WebService, just add the [WebMethod] attribute to the method!

If you add cache, then [WebMethod(CacheDurition=600)]

Instantiate WebService

FriendsService.FriendsInfo fi = new FriendsService.FriendsInfo(); 
String userid; 
Userid = fi.GetUserID(“…”);

Tips!

HyperLink reg = new HyperLink(); 
Reg.ToolTip = “… …”;

Checkout:

System.Web.Security.Forms.Authentication.SignOut(); 
Response.write (Request.ApplicaltionPath);

Trace debugging:

Trace.Write 
Trace.Warn

Exception:

1. Throws exception

Program exception throws

Throw new ***Exception(“…”);

2． Catch exceptions

It must be thrown from a try code block at the beginning. The try code block is used to place all codes that may throw exceptions.

Eg:

Try 
                  { 
                            … … 
                  } 
         Catch(ArgumentNullExeption e) 
                  { 
                            … 
                  }

Unhandled exception web.config setting

<Custom Errors mode = “on” defaultRedriect = “customerror.aspx”; />

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