asp.net如何使用check availlable controle使用？

Question

我在確定 書是可用還是不可用。如何檢查，然後如何設置驗證CONTROLE 我的編碼書的一頁問題創造庫管理系統中的一個網站是

public partial class Issueofbook : System.Web.UI.Page 
{ 
    public Int64 Sid; 

    protected void Page_Load(object sender, EventArgs e) 
    { 
     string Id; 
     Id = Request.QueryString.Get(0); 

     if (!(IsPostBack == true)) 
     { 
      if (Request.QueryString.Get(1) == "G") 
      { 
       Sid = Convert.ToInt64(Id); 
       if (PopulatedRecord(Sid) == false) 
       { 

       } 
      } 
     } 
    } 
    private Boolean PopulatedRecord(Int64 Id) 
    { 
     DataSet DS; 
     DS = new DataSet(); 
     SqlCommand cmd = new SqlCommand(); 
     SqlDataAdapter da = new SqlDataAdapter(); 
     SqlConnection Cnn = new SqlConnection(); 
     string connectionstring; 
     connectionstring = @"Datasource=DEVI\SQLEXPRESS;Intial             
        catalog=librarymanagement;Integrated Security=SSPI"; 
     Cnn.ConnectionString = connectionstring; 
     if (Cnn.State != ConnectionState.Open) 
      Cnn.Open(); 
     cmd.Connection = Cnn; 
     cmd.CommandType = CommandType.StoredProcedure; 
     cmd.CommandText = "usbinsertdatainto"; 
     cmd.Parameters.Clear(); 
     cmd.Parameters.AddWithValue("@bookno", txtno); 
     da.SelectCommand = cmd; 
     try 
     { 
      da.Fill(DS); 
     } 
     catch (Exception ex) 
     { 
      throw new ApplicationException(
       "!!! An Error Occured While Update Record In Dtl_SecurityCapital_Upload." + 
      ex.Message); 
      lblerror.Visible = true; 
      lblerror.Text = "!!! An Error Occured While " + ex.Message.ToString(); 
      return false; 
     } 
     if (DS.Tables[0].Rows.Count > 0) 
     { 
      txtno.Text = DS.Tables[0].Rows[0]["bookno"].ToString(); 
      txtstuno.Text = DS.Tables[0].Rows[0]["studentno"].ToString(); 
      RadioButton1.Text = DS.Tables[0].Rows[0]["copiesavaillable"].ToString(); 
      RadioButton2.Text = DS.Tables[0].Rows[0]["copiesavaillable"].ToString(); 
      txtdate.Text = DS.Tables[0].Rows[0]["IssueDate"].ToString(); 
      txtddate.Text = DS.Tables[0].Rows[0]["Duedate"].ToString(); 
     } 
     cmd.Dispose(); 
     Cnn.Close(); 
     Cnn.Dispose(); 
     return true; 
    } 

    protected void Btn_click(object sender, EventArgs e) 
{ 
    SqlCommand cmd = new SqlCommand(); 
    SqlConnection cnn = new SqlConnection(); 
    string connectionstring; 
    connectionstring = ConfigurationManager.ConnectionStrings["librarymanagementconnectionstring"].ConnectionStri 
     ng; 
    cnn.ConnectionString = connectionstring; 
    if (cnn.State != ConnectionState.Open) 
     cnn.Open(); 
    cmd.Connection = cnn; 
    cmd.CommandType = CommandType.StoredProcedure; 
    cmd.CommandText = "spupdatebookdetail"; 
    cmd.Parameters.Clear(); 
    cmd.Parameters.AddWithValue("@bookno", txtno.Text); 
    cmd.Parameters.AddWithValue("@studentno", txtstuno.Text); 
    cmd.Parameters.AddWithValue("@Issuedate", txtdate.Text); 
    cmd.Parameters.AddWithValue("@Duedate", txtddate.Text); 
    if(RadioButton1.Checked ==true) 
    { 
     cmd.Parameters.AddWithValue("@copiesavaillable", RadioButton1.Text); 
    } 
    if (RadioButton2.Checked==true) 
    { 
     cmd.Parameters.AddWithValue("@copiesavillable", RadioButton2.Text); 
    } 
    try 
    { 
     cmd.ExecuteNonQuery(); 
    } 
    catch (Exception ex) 
    { 
     throw new ApplicationException("!!! An error an occured while update the record In Dtl _captial upload." + ex.Message); 
     lblerror.Visible = true; 
     lblerror.Text = "!!! An error an occured while." + ex.Message.ToString(); 
    } 
    lblerror.Visible = true; 
    lblerror.Text = "Record update sucessfully"; 
    PopulatedRecord(Sid); 
} 

    protected void Button_click(object sender, EventArgs e) 
    { 
     Server.Transfer("useraccount.aspx"); 
    } 

    protected void Button2_Click(object sender, EventArgs e) 
    { 

     SqlConnection cnn = new SqlConnection(); 
     string constr = null; 
     SqlCommand cmd = new SqlCommand(); 
     constr = @"Data Source=DEVI\SQLEXPRESS; Initial Catalog =librarymanagement; Integrated Security=SSPI"; 
     cnn.ConnectionString = constr; 
     try 
     { 
      if (cnn.State != ConnectionState.Open) 
       cnn.Open(); 
     } 
     catch (Exception ex) 
     { 
      string str1 = null; 
      str1 = ex.ToString(); 
     } 
     cmd.Connection = cnn; 
     cmd.CommandType = CommandType.StoredProcedure; 
     cmd.CommandText = "uspInsertbookDatainto"; 
     cmd.Parameters.Clear(); 
     cmd.Parameters.AddWithValue("@bookno", txtno.Text); 
     cmd.Parameters.AddWithValue("@studentno", txtstuno.Text); 
     cmd.Parameters.AddWithValue("@Issuedate", txtdate.Text); 
     cmd.Parameters.AddWithValue("@Duedate", txtddate.Text); 
     if (RadioButton1.Checked == true) 
     { 
      cmd.Parameters.AddWithValue("@copiesavaillable", RadioButton1.Text); 
     } 
     if (RadioButton2.Checked == true) 
     { 
      cmd.Parameters.AddWithValue("@copiesavaillable", RadioButton2.Text); 
     } 
     try 
     { 
      cmd.ExecuteNonQuery(); 
     } 
     catch (Exception ex) 
     { 
      throw new ApplicationException("!!! An error an occured while Insert Record Dtl_SecurityCapital_Upload." + ex.Message); 
      lblerror.Visible = true; 
      lblerror.Text = "!!! An Error occured while ." + ex.Message.ToString(); 
     } 

     finally 
     { 
      cmd.Dispose(); 
     } 
     cnn.Close(); 
     lblerror.Text = "New Issue of record suceessfully!!"; 
     txtno.Text = ""; 
     txtstuno.Text = ""; 
     txtdate.Text = ""; 
     txtddate.Text = ""; 
    } 

} 

Answer 1

在你的代碼中有一些看起來怪怪的東西。例如(!(IsPostBack == true))應該可能是(!IsPostBack)。此外，你應該檢查的查詢字符串參數的存在和名字Request.QueryString["name"] 把它做到這一點，而不是

string id = Request.QueryString["id"]; 
if (id == null) 
{ 
    // do error handling here, no id specified; 
} 
else 
{ 
    // use id; 
} 

...更多

你能不能更具體的，以什麼實際問題是，除了它不運行？