ViewState and DataTable dynamic input data sample

  This article mainly introduces viewstate and DataTable dynamic input data samples, need friends can refer to the following

    Code as follows: <%@ Page language= "C #" enableviewstate= "true"%> <%@ Import namespace= "System.Data"%> ;! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en"   "http://www.w3.org/TR/xhtml1/DTD/ Xhtml1-transitional.dtd "> <script runat=" Server ">   private DataTable stovetable = null;   protected void Page_Load (object sender, EventArgs e)   {    if (!) Page.IsPostBack)     {     //create EmptyDataTemplate       this. Gridview_list. DataBind ();    }  }     protected void Gridview_list_rowdatabound (object sender, GridViewRowEventArgs e) &n Bsp {    if (E.row.rowtype = datacontrolrowtype.datarow)     {      String usage = Datab Inder. Eval (E.row.dataitem, "usage"). ToString ();       String steelkind = DataBinder.Eval (E.row.dataitem, "Steelkind"). ToString ();       String Castington = DataBinder.Eval (e.row. DataItem, "Castington"). ToString ();       DropDownList x1 = E.row.findcontrol ("x1") as DropDownList;       DropDownList x2 = E.row.findcontrol ("x2") as DropDownList;       TextBox x3 = E.row.findcontrol ("x3") as TextBox;       X3. Text = Castington;       ListItem xx1 = x1. Items.findbyvalue (usage);       if (xx1!= null) xx1. Selected = true;       ListItem xx2 = x2. Items.findbyvalue (Steelkind);       if (xx2!= null) xx2. Selected = true;    }  }     protected void LinkButton1_Click (object sender, EventArgs e)   {    DropDownList x1, x2;     TextBox x3;     if (gridview_list. Rows.Count = 0)     {      x1 = gridview_list. Controls[0]. Controls[0]. FindControl ("x1") as DropDownList;       x2 = gridview_list. Controls[0]. Controls[0]. FindControl ("X2") as DropDownList;       x3 = gridview_list. Controls[0]. Controls[0]. FindControl ("x3") as TextBox;    }     Else     {      GridViewRow r = gridview_list. Footerrow;       x1 = R.findcontrol ("x1") as DropDownList;       x2 = R.findcontrol ("x2") as DropDownList;       x3 = R.findcontrol ("x3") as TextBox;    }     if (viewstate["dt"] = null)     {      stovetable = new DataTable ();       STOVETABLE.COLUMNS.ADD ("Usage", typeof (String));       STOVETABLE.COLUMNS.ADD ("Steelkind", typeof (String));       STOVETABLE.COLUMNS.ADD ("Castington", typeof (String));    }     Else     {      stovetable = (DataTable) viewstate["DT"];   &N Bsp }     DataRow NewRow = Stovetable.newrow ();     newrow["usage"] = x1. SelectedValue;     newrow["steelkind"] = x2. SelectedValue;     newrow["Castington"] = x3. Text;     STOVETABLE.ROWS.ADD (NewRow);       viewstate["dt"] = stovetable;     this. Gridview_list. DataSource = stovetable;     this. Gridview_list. DataBind ();    }   protected void Linkbutton2_click (object sender, EventArgs e)   {    if (viewstate[) DT "] = = null)     {      return;    }     stovetable = (DataTable) ViewState ["DT"];     if (StoveTable.Rows.Count < 1) return;     StoveTable.Rows.RemoveAt (stovetable.rows.count-1);     viewstate["dt"] = stovetable;     this. Gridview_list. DataSource = stovetable;     this. Gridview_list. DataBind ();  }     protected void x1_selectedindexchanged (object sender, EventArgs e)   {    DROPDOWNL IST x1 = sender as DropDownList;     GridViewRow r = x1. Parent.parent as GridViewRow; &nbsp   if (viewstate["dt"] = = null)     {      Response.Write ("Error");       RET Urn    }     stovetable = (DataTable) viewstate["DT"];     stovetable.rows[r.rowindex]["usage"] = x1. SelectedValue;     viewstate["dt"] = stovetable;     this. Gridview_list. DataSource = stovetable;     this. Gridview_list. DataBind ();  }     protected void x2_selectedindexchanged (object sender, EventArgs e)   {    DROPDOWNL ist x2 = sender as DropDownList;     GridViewRow r = X2. Parent.parent as GridViewRow;     if (viewstate["dt"] = null)     {      Response.Write ("Error");     &NB Sp Return    }     stovetable = (DataTable) viewstate["DT"];     stovetable.rows[r.rowindex]["steelkind"] = x2. SelectedValue;     viewstate["dt"] = stovetable;     this. Gridview_list. DatAsource = stovetable;     this. Gridview_list. DataBind ();  }     protected void x3_textchanged (object sender, EventArgs e)   {      TextBox x3 = sender as TextBox;     GridViewRow r = x3. Parent.parent as GridViewRow;     if (viewstate["dt"] = null)     {      Response.Write ("Error");     &NB Sp Return    }     stovetable = (DataTable) viewstate["DT"];     stovetable.rows[r.rowindex]["Castington"] = x3. Text;     viewstate["dt"] = stovetable;     this. Gridview_list. DataSource = stovetable;     this. Gridview_list. DataBind ();  } </script> <html xmlns= "http://www.w3.org/1999/xhtml" > <head id= "Head1" runat= "Server" >   <title></title> </head> <body>   <form id= "Form1" runat= "Server" >   < Asp:gridview id= "gridview_list" runat= "Server" showfooter= "true" AutogeneraTecolumns= "false"     onrowdatabound= "Gridview_list_rowdatabound" >     <emptydatatemplate >       <table style= "border-collapse:collapse; width:100% "cellspacing=" 0 "rules=" all "        border=" 1 ">         <tr>           <th scope= "col" >             Select 1     &NB Sp     </th>           <th scope= "col" >           &NB Sp Option 2           </th>           <th scope= "col" >             input text           </th>         </tr> & nbsp       <tr><td>           <asp:dropdownlist id= "x1" runat= "Server" & Gt             <ASP:LISTITEM>L0≪/asp:listitem>             <asp:ListItem>L1</asp:ListItem>             <asp:ListItem>L2</asp:ListItem>             <asp :listitem>l3</asp:listitem>           </asp:DropDownList>       & nbsp </td><td>           <asp:dropdownlist id= "x2" runat= "Server" >     &N Bsp       <asp:ListItem>10#</asp:ListItem>             <asp: listitem>20#</asp:listitem>             <asp:listitem>30#</asp: listitem>             <asp:ListItem>40#</asp:ListItem>           </asp:DropDownList>         </td><td>         &NBS P <asp:textbox id= "x3" runat= "SerVer "></asp:TextBox>         </td></tr>       </table> & nbsp   </EmptyDataTemplate>     <Columns>       <asp:templatefield headertext= Option 1 ">         <ItemTemplate>           <asp:dropdownlist id=" x1 " runat= "Server" autopostback= "true" onselectedindexchanged= "x1_selectedindexchanged" >         & nbsp   <asp:ListItem>L0</asp:ListItem>             <ASP:LISTITEM>L1 </asp:ListItem>             <asp:ListItem>L2</asp:ListItem>             <asp:ListItem>L3</asp:ListItem>           </as p:dropdownlist>         </ItemTemplate>         <FooterTemplate> & nbsp         <asp:D ropdownlist id= "x1" runat= "Server" >             <asp:listitem>l0</asp: listitem>             <asp:ListItem>L1</asp:ListItem>       & nbsp     <asp:ListItem>L2</asp:ListItem>             <asp:listitem >L3</asp:ListItem>           </asp:DropDownList>         < /footertemplate>       </asp:TemplateField>       <asp:templatefield headertext= "SELECT 2" >         <ItemTemplate>           <asp:dropdown List id= "x2" runat= "Server" autopostback= "true" onselectedindexchanged= "x2_selectedindexchanged" >             <asp:ListItem>10#</asp:ListItem>             <as P:listitem>20#</asp:listitem>     &nbsp       <asp:ListItem>30#</asp:ListItem>             <asp: listitem>40#</asp:listitem>           </asp:DropDownList>       & nbsp </ItemTemplate>         <FooterTemplate>           <ASP:DROPD Ownlist id= "x2" runat= "Server" >             <asp:listitem>10#</asp:listitem >             <asp:ListItem>20#</asp:ListItem>         &N Bsp   <asp:ListItem>30#</asp:ListItem>             <asp:listitem>40# </asp:ListItem>           </asp:DropDownList>         </foote rtemplate>       </asp:TemplateField>       <asp:templatefield headertext= " Input text ">       &nbsp <ItemTemplate>           <asp:textbox id= "x3" runat= "Server" autopostback= "true" Ontextchanged= "x3_textchanged" ></asp:TextBox>         </ItemTemplate>         <FooterTemplate>           <asp:textbox id= "x3" runat= "Server" > </asp:TextBox>         </FooterTemplate>       </asp:templatefield >     </Columns>   </asp:GridView>   <asp:linkbutton id= "LinkButton1" runat= Server "text=" Add Content "onclick=" LinkButton1_Click "></asp:LinkButton>   <asp:linkbutton id=" LinkButton2 "runat=" server "text=" Delete content "onclick=" Linkbutton2_click "></asp:LinkButton>   </form> </body> </html>