Behind code for bound asp:label

Question

Hi Pretty new to asp. I have been looking at many samples and have got as far as I can and now need real help; My page contains an asp:Datalist and has two controls:- : Image ID =Image1 runat =server ImageUrl = ' # Eval(FilePath)%> ' Width = 100px Height = 100px /> /> If I omit the asp:Label the page runs and I get the pictures. However the page will not run with the label. I know there should be something in the code behind I guess to bind the FileName data. But I am not sure what this should be and where I should put it. Any help gratefully recieved. Thanks Hi Very new to asp. I have a datalist which has an image control. This works when I run the aspx page. When I add an asp:Label the page will not run. I know I have to bind the info FileName in the code behind but I do not know what this should be and where it should be placed. Any help gratefully received. Thanks.

Datta Kharad · Answer

Hi Did you solve your problem or not?

Kevin · Answer

Great Many thanks

Datta Kharad · Answer

Hi I have seen your attachment (project1.zip) after I did it in my previous example So you can check my example and implement in your project. Datalist is a very powerful control with one drawback that it does not have built-in paging capability a feature the DataGrid offers. to provide paging to datalist we can either use PagedDataSource class found in the System.Web.UI.WebControls namespace for auto paging like the datagrid or implement custom paging functionality. You can also use ListView control with datapager anyway now I am doing what you said ie (FirstLastNextPrevious and also Numbering) using Datalist with custom paging. See in below code or Attachment File with Example. //In Source File onitemdatabound=DataList1_ItemDataBound CellPadding=2 RepeatColumns=3 RepeatLayout = Table> ' Width = 100px Height = 100px/> First Previous OnItemDataBound=dlPaging_ItemDataBound> ' CommandName=Paging Text=' '> OnClick=lbtnNext_Click>Next Last //===================================================== //In Code File using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Configuration; using System.Data.SqlClient; using System.Data; public partial class _Default : System.Web.UI.Page { SqlConnection con; SqlCommand cmd; SqlDataAdapter da; PagedDataSource _PageDataSource = new PagedDataSource(); string sConnectionStr = ConfigurationManager.ConnectionStrings[ConnectionString].ConnectionString; protected void Page_Load(object sender EventArgs e) { con = new SqlConnection(sConnectionStr); con.Open(); if (!IsPostBack) { BindItemsList(); } } private int CurrentPage { get { object objPage = ViewState[_CurrentPage]; int _CurrentPage = 0; if (objPage == null) { _CurrentPage = 0; } else { _CurrentPage = (int)objPage; } return _CurrentPage; } set { ViewState[_CurrentPage] = value; } } private int fistIndex { get { int _FirstIndex = 0; if (ViewState[_FirstIndex] == null) { _FirstIndex = 0; } else { _FirstIndex = Convert.ToInt32(ViewState[_FirstIndex]); } return _FirstIndex; } set { ViewState[_FirstIndex] = value; } } private int lastIndex { get { int _LastIndex = 0; if (ViewState[_LastIndex] == null) { _LastIndex = 0; } else { _LastIndex = Convert.ToInt32(ViewState[_LastIndex]); } return _LastIndex; } set { ViewState[_LastIndex] = value; } } private void BindItemsList() { DataTable dataTable = CreateDataSource(); _PageDataSource.DataSource = dataTable.DefaultView; _PageDataSource.AllowPaging = true; _PageDataSource.PageSize = 6; _PageDataSource.CurrentPageIndex = CurrentPage; ViewState[TotalPages] = _PageDataSource.PageCount; this.lblPageInfo.Text = Page  + (CurrentPage + 1) +  of  + _PageDataSource.PageCount; this.lbtnPrevious.Enabled = !_PageDataSource.IsFirstPage; this.lbtnNext.Enabled = !_PageDataSource.IsLastPage; this.lbtnFirst.Enabled = !_PageDataSource.IsFirstPage; this.lbtnLast.Enabled = !_PageDataSource.IsLastPage; this.DataList1.DataSource = _PageDataSource; this.DataList1.DataBind(); this.doPaging(); } protected DataTable CreateDataSource() { DataTable dt = new DataTable(); string sSQL = Select * from tbSample; cmd = new SqlCommand(sSQL con); da = new SqlDataAdapter(cmd); da.Fill(dt); // DataView dv = new DataView(dt); return dt; } /// /// Binding Paging List /// private void doPaging() { DataTable dt = new DataTable(); dt.Columns.Add(PageIndex); dt.Columns.Add(PageText); fistIndex = CurrentPage - 5; if (CurrentPage > 5) { lastIndex = CurrentPage + 5; } else { lastIndex = 10; } if (lastIndex > Convert.ToInt32(ViewState[TotalPages])) { lastIndex = Convert.ToInt32(ViewState[TotalPages]); fistIndex = lastIndex - 10; } if (fistIndex { fistIndex = 0; } for (int i = fistIndex; i { DataRow dr = dt.NewRow(); dr[0] = i; dr[1] = i + 1; dt.Rows.Add(dr); } this.dlPaging.DataSource = dt; this.dlPaging.DataBind(); } protected void lbtnNext_Click(object sender EventArgs e) { CurrentPage += 1; this.BindItemsList(); } protected void lbtnPrevious_Click(object sender EventArgs e) { CurrentPage -= 1; this.BindItemsList(); } protected void dlPaging_ItemCommand(object source DataListCommandEventArgs e) { if (e.CommandName.Equals(Paging)) { CurrentPage = Convert.ToInt16(e.CommandArgument.ToString()); this.BindItemsList(); } } protected void dlPaging_ItemDataBound(object sender DataListItemEventArgs e) { LinkButton lnkbtnPage = (LinkButton)e.Item.FindControl(lnkbtnPaging); if (lnkbtnPage.CommandArgument.ToString() == CurrentPage.ToString()) { lnkbtnPage.Enabled = false; lnkbtnPage.Style.Add(fone-size 14px); lnkbtnPage.Font.Bold = true; } } protected void lbtnLast_Click(object sender EventArgs e) { CurrentPage = (Convert.ToInt32(ViewState[TotalPages]) - 1); this.BindItemsList(); } protected void lbtnFirst_Click(object sender EventArgs e) { CurrentPage = 0; this.BindItemsList(); } protected void DataList1_ItemDataBound(object sender DataListItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { Label Label1 = (Label)e.Item.FindControl(Label1); Label1.Text = DataBinder.Eval(e.Item.DataItem FileName).ToString(); } } }

Kevin · Answer

Hi Again thanks. Works fine. As there are more than 3000 images (and growin) I have added some paging. Although the images  lnkbtns and page numbers all show the paging is not working. I have got this set to 15 on the dynamic dropdownlist. Actually I think I would prefer to have settings for the number of images per page and say 10 variable paging numbers. Anyway the first problem is paging is not working correctly. From what you have said previously I guess it is something to do with the dataview v datatable. If you can help great.

Datta Kharad · Answer

Hi Yes you can also use protected DataView but you cant use protected void b'coz it will return nothing and our method require DataView to bind datalist if you want do this(private void) then do one thing... 1) Create method which was mentioned in your recently post in that write query and get result in datatable but you should be bind via dataview instead of bind datatable to directly datalist. Example:- protected void Page_Load(object sender EventArgs e) { con = new SqlConnection(sConnectionStr); con.Open(); if (!IsPostBack) { BindData(); } } private void BindData() { DataTable dt = new DataTable(); string sSQL = Select * from tbSample; cmd = new SqlCommand(sSQL con); da = new SqlDataAdapter(cmd); da.Fill(dt); DataView dv = new DataView(dt); DataList1.DataSource = dv ; //Here datalist bind using dataview instead of datatable. DataList1.DataBind(); } protected void DataList1_ItemDataBound(object sender DataListItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { Label Label1 = (Label)e.Item.FindControl(Label1); Label1.Text = DataBinder.Eval(e.Item.DataItem FileName).ToString(); } }

Kevin · Answer

Hi Forgot the connection string SqlDataAdapter da = new SqlDataAdapter (SQL AlbumImages ); Thanks

Kevin · Answer

Hi I was wondering why the use of 'public dataview createdatasource' and not 'protectected void *******. I have seen this many times in samples. I tried to change the code for this but I get the error message Format of the initialization string does not conform to specification starting at index 0. is there something wrong with the connection string or is it the da.fill My code is private void BindDataSource string SQL = Select * from tblFiles Order by FileName; DataTable dt = new DataTable(); string SQL = Select * from tblFiles Order By FileName ; da.Fill(dt); DataList1.DataSource = dt; DataList.DataBind(); Thanks

Datta Kharad · Answer

Hi 1) I don't have idea about your first problem. 2) Ans:- Yes asp:Label has contained within the ItemTemplate.

Jignesh Trivedi · Answer

hi try this ' Width = 100px Height = 100px /> ' /> hope this help.

Kevin · Answer

Hi First of all a mega thanks for all your work. I shall be spending quite a bit of time seeing how it works. A couple of quick questions: 1. Depending on the length of the text in the label (123 lines) I notice the images move up/down and therefore from an asethic point of view is not good on the eye. Is there any method to resolve this. I have tried but I cannot correct. 2. Am I correct in assuming that the asp:label has to be contained within the ItemTemplate I cannot move it to say the 'Footer' area. Once again many thanks.

Datta Kharad · Answer

Hi I tried this example and its working and I am writing example and also sending attachment file (File with database) try this example i think it will work. In sourse file:- onitemdatabound=DataList1_ItemDataBound RepeatColumns = 2 RepeatLayout = Table Width = 500px> --%> ' Width = 100px Height = 100px/> //=================================================== Code file:- using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Configuration; using System.Data.SqlClient; using System.Data; public partial class _Default : System.Web.UI.Page { SqlConnection con; SqlCommand cmd; SqlDataAdapter da; string sConnectionStr = ConfigurationManager.ConnectionStrings[ConnectionString].ConnectionString; protected void Page_Load(object sender EventArgs e) { con = new SqlConnection(sConnectionStr); con.Open(); if (!IsPostBack) { DataList1.DataSource = CreateDataSource(); DataList1.DataBind(); } } public DataView CreateDataSource() { DataTable dt = new DataTable(); string sSQL = Select * from tbSample; cmd = new SqlCommand(sSQL con); da = new SqlDataAdapter(cmd); da.Fill(dt); DataView dv = new DataView(dt); return dv; } protected void DataList1_ItemDataBound(object sender DataListItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { Label Label1 = (Label)e.Item.FindControl(Label1); Label1.Text = DataBinder.Eval(e.Item.DataItem FileName).ToString(); //Label1.Text =((DataRowView)e.Item.DataItem).Row.ItemArray[0].ToString(); } } }

Kevin · Answer

Hi I did make the change. I must have sent the wrong file. Anyway I have rechecked the code in oder that it matches yours. Error code on run is:- DataBinding: 'System.Data.DataRowView' does not contain a property with the name 'FileName' Thanks

Datta Kharad · Answer

Hi You didn't change which was i posted previously...anyway I am inserting all lines and also see in attchment. *.aspx =========== RepeatColumns = 5 RepeatLayout = Table Width = 500px> ' Width = 100px Height = 100px /> asp:Label ID=Label1 runat=server /> *.aspx.cs ============== protected void DataList1_ItemDataBound(object sender DataListItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { Label Label1 = (Label)e.Item.FindControl(lblFileName); lblNAme.Text = DataBinder.Eval(e.Item.DataItem FileName).ToString(); } }

Kevin · Answer

Hi No luck error message on run:- DataBinding: 'System.Data.DataRowView' does not contain a property with the name 'FileName'. Thanks

Datta Kharad · Answer

Hi You can get it using databinder try this line Label Label1 = ( Label )e.Item.FindControl( lblFileName ); Label1.Text = DataBinder.Eval(e.Item.DataItem FileName).ToString();

Kevin · Answer

Hi No luck. The error message is Object reference not set to an instance of an object I did notice that there was a space between  DataList1 _ItemDataBound which I have removed so that it matches that contained in the code behind. I have amended the code behind to read Label Label1 = ( Label )e.Item.FindControl( lblFileName ); Label1.Text = F ileName from AlbumImages ; The database name is AlbumImages the table name is tblFiles and the column heading is FileName. If I do not change the code I get the same error message. Thanks .dlTable { border:double 1px #D9D9D9; width:100px; text-align:left; } .style1 { width: 240px; } .style2 { width: 403px; }

Datta Kharad · Answer

Hi Kevin You have to change the Label control ie use this line or see in attachment file. instead of this line ' /> Because of you will get text of lebel in Code file(Databound event) need not to be write Text ( Text = ' ' ) in source file. Only write label id and runat='server as like above red highlighted line.

Kevin · Answer

Hi Many thanks everybody's help. I have made the changes to bind the data but I am getting error message:- DataBinding: 'System.Data.DataRowView' does not contain a property with the name 'FileName'. amended code:- protected void DataList1_ItemDataBound(object sender DataListItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { Label Label1 = (Label)e.Item.FindControl(lblFileName); Label1.Text = file name; Thanks

Datta Kharad · Answer

Hi You have to generate databound event of Datalist see in below code or attachment file. onitemdatabound = DataList1 _ItemDataBound> ' Width = 100px Height = 100px /> protected void DataList1_ItemDataBound(object sender DataListItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { Label lblNAme = (Label)e.Item.FindControl(lblImageName); //Here you will get id lblNAme.Text = image name from database; } }