Develop Reference

click event for dynamic button inside a datalist

I have a DataList and bind it corrertly.
SqlCommand cmd = new SqlCommand(str_cmd, conn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
dtlst_periodicTask.DataSource = ds;
dtlst_periodicTask.DataBind();
pds.DataSource = ds.Tables[0].DefaultView;
pds.AllowPaging = true;
pds.PageSize = 25;
pds.CurrentPageIndex = CurrentPage;
lnkbtnNext.Enabled = !pds.IsLastPage;
lnkbtnPrevious.Enabled = !pds.IsFirstPage;
and some codes for paging.
After that, I need to add a number of Buttons in each row dynamically because the number of buttons is not fix.
foreach (DataListItem item in dtlst.Items)
{
Button btn = new Button();
btn.Click += new EventHandler(btn_Click);
pnl_users.Controls.Add(btn);
}
But the button click event does not work.
protected void btn_Click(object sender, EventArgs e)
{
// code does not fire.
}
When I put a Button in .aspx page, have access and it works.
protected void dtlst object source, DataListCommandEventArgs e)
{
}

but why are you attempting to inject a button?
Why not just include the button in the markup in the first place? I can't really see the need or reason to layout a datalist, and THEN decide to use code?
Just drag + drop in a button into the datalist, and you are quite much done.
So here is our datalist - we dropped in a plane jane button.
<asp:DataList ID="DataList1" runat="server" DataKeyField="ID" >
<ItemTemplate>
<div style="border-style:solid;color:black;width:300px;margin-left:25px">
<div id="mybox" runat="server" style="padding:5px;text-align:right">
<p>Hotel Name: <asp:TextBox ID="HotelName" runat="server" Text ='<%# Eval("HotelName") %>' /></p>
<p>First Name: <asp:TextBox ID="FirstName" runat="server" Text ='<%# Eval("FirstName") %>' /></p>
<p>Last Name: <asp:TextBox ID="LastName" runat="server" Text ='<%# Eval("LastName") %>' /></p>
<p>City: <asp:TextBox ID="City" runat="server" Text ='<%# Eval("City") %>' /></p>
<p>Province: <asp:TextBox ID="Province" runat="server" Text ='<%# Eval("Province") %>' /></p>
Active: <asp:CheckBox ID="Active" runat="server" Checked = '<%# Eval("Active") %>'/>
<br />
<asp:Button ID="cmdRow" runat="server" Text="Row click This item"
/>
</div>
</div>
<div style="height:15px"></div>
</ItemTemplate>
</asp:DataList>
And our code to fill looks like this:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
MyLoadData();
}
void MyLoadData()
{
using (SqlConnection con = new SqlConnection(Properties.Settings.Default.TEST4))
{
string strSQL = "SELECT TOP 3 * FROM tblHotels ORDER BY HotelName";
using (SqlCommand cmdSQL = new SqlCommand(strSQL, con))
{
con.Open();
DataList1.DataSource = cmdSQL.ExecuteReader();
DataList1.DataBind();
}
}
And we now have this:
Now, lets wire up the button click, like this:
so, create new event in above (inteli-sense offers this choice).
protected void cmdRow_Click(object sender, EventArgs e)
{
Button btn = (Button)sender;
DataListItem gRow = (DataListItem)btn.Parent;
Debug.Print("Row index = " + gRow.ItemIndex.ToString());
int pkID = (int)(DataList1.DataKeys[gRow.ItemIndex]);
Debug.Print("Data base PK id = " + pkID.ToString());
Debug.Print("Hotel name = " + ((TextBox)(gRow.FindControl("HotelName"))).Text);
Debug.Print("City = " + ((TextBox)(gRow.FindControl("City"))).Text);
Debug.Print("--------------------");
}
And out output is this:
Row index = 1
Data base PK id = 72
Hotel name = Banff Rocky Mountain Resort
City = Banff
--------------------
so, it not at all clear why you want to spend the time, effort, and that of writing code when you can as a general rule just drop in a good old plane jane button from the designer right into the datalist, and then simple wire up a event.
Edit:
You can lead a horse to water - but can you get the horse to drink the water?
You can as noted inject a button, but I REALLY but REALLY but REALLY do not recommend doing this.
However, to get the button click event to work, then you can do this:
HtmlButton btn = new HtmlButton();
btn.InnerText = "Index " + e.Item.ItemIndex;
btn.Attributes.Add("onclick","__doPostBack('BtnTest2','')");
btn.ViewStateMode = ViewStateMode.Enabled;
HtmlGenericControl MyDiv = (HtmlGenericControl)e.Item.FindControl("mybox");
MyDiv.Controls.Add(btn);
Edit2:
Ok, there seems to be a issue of persistence.
So, adding MUST occur on page load (or could be earlier).
And the buttons have to be re-inserted each time on post-backs.
This now works:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
MyLoadData();
}
AddBtns();
}
void MyLoadData()
{
using (SqlConnection con = new SqlConnection(Properties.Settings.Default.TEST4))
{
string strSQL = "SELECT TOP 3 * FROM tblHotels ORDER BY HotelName";
using (SqlCommand cmdSQL = new SqlCommand(strSQL, con))
{
con.Open();
DataList1.DataSource = cmdSQL.ExecuteReader();
DataList1.DataBind();
}
}
}
void AddBtns()
{
foreach (DataListItem gRow in DataList1.Items)
{
Button btn = new Button();
btn.Text = "Index " + gRow.ItemIndex;
btn.ID = "Btn" + gRow.ItemIndex;
btn.Click += new EventHandler(BtnTest3);
HtmlGenericControl MyDiv = (HtmlGenericControl)gRow.FindControl("mybox");
MyDiv.Controls.Add(btn);
}
}
void BtnTest3(object sender, EventArgs e)
{
Debug.Print("buttn3 click");
}
Note two changes:
We don't add/inject the buttons ONLY on !IsPostback.
We inject the buttons each time on page load
We did not use the Item bound event.

Display DropDownlist when click on specific cell asp.net table

I am trying to figure it out how can I display a dropDownList on a specific cell in the table right after clicking a button "Show DropDownlist" located on that cell.
This is the behind code , right now it is displaying the dropDownList at the last cell of each row. and I want to make it appear only when a button is clicked.
while (rdr.Read())
{
TableRow tRow = new TableRow();
myTable.Rows.Add(tRow);
for (int i = 0; i <= 4; i++)
{
// Create a new cell and add it to the row.
TableCell tCell = new TableCell();
if (i == 4)
{
tCell.Controls.Add(SM_List()); //Adding the dropdownlist
tRow.Cells.Add(tCell);
continue;
}
tCell.Text = rdr.GetString(i);
tCell.Attributes.Add("onmouseover", "this.style.cursor = 'pointer'; this.style.backgroundImage = ''; ");
tCell.Attributes.Add("onClick", "getData()");
tRow.Cells.Add(tCell);
}
/* iterate once per row */
}
I want to add this code, so it will be a button at first , instead of a drop down list :
Button bt = new Button();
bt.Text = "Switch";
bt.Click += new EventHandler(DropDownList_Show);
tCell.Controls.Add(bt);
But I am not sure how to display the DropDownList at the exact cell the button was located. and also I want to do some actions when Value was selected in the dropdownlist.
Can you please assist , I feel a little bit lost.

You can solve this issue easily by using GridView in ASP.NET.
Let say the GridView is declared as following in ASPX page.
<asp:GridView ID="GridView1" runat="server" OnRowCommand="GridView1_RowCommand" AutoGenerateColumns="false">
<Columns>
<asp:BoundField DataField="Id" />
<asp:BoundField DataField="Token" />
<asp:BoundField DataField="Secret" />
<asp:ButtonField CommandName="ShowDropDown" Text="Show" />
<asp:TemplateField>
<ItemTemplate>
<asp:DropDownList ID="dropDownList" runat="server" Visible="false">
<asp:ListItem Text="Valid" Value ="1"></asp:ListItem>
<asp:ListItem Text="Invalie" Value ="2"></asp:ListItem>
</asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Following is the method in code behind which populates the GridView.
private void BindGridView()
{
var tokens = new List<AccessToken>();
using (var conn = new SqlConnection("Server=somedbserver;Database=somedatabase;User Id=someuser;Password=somepassword;"))
{
using (var command = new SqlCommand())
{
command.Connection = conn;
command.CommandText = "SELECT Id, Token, Secret FROM Tokens";
command.CommandType = System.Data.CommandType.Text;
conn.Open();
using (var reader = command.ExecuteReader())
{
while (reader.Read())
{
var token = new AccessToken();
token.Id = reader.GetInt32(0);
token.Token = reader.GetString(1);
token.Secret = reader.GetString(2);
tokens.Add(token);
}
}
}
}
GridView1.DataSource = tokens;
GridView1.DataBind();
}
And I am calling this method in Page_Load.
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
BindGridView();
}
}
Following is the event handler of RowCommand event of GridView which will display the dropdown list in the column next to the button which is clicked.
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
if(e.CommandName == "ShowDropDown")
{
var row = GridView1.Rows[Convert.ToInt32(e.CommandArgument)];
//Using Cell[4] coz the Dropdownlist is in 5th column of the row.
//You need to replace 4 with appropriate column index here.
//Also replace "dropDownList" with the ID assigned to the dropdown list in ASPX.
var ddl = (DropDownList)row.Cells[4].FindControl("dropDownList");
if(ddl != null)
{
ddl.Visible = true;
}
}
}
You will able resolve your issue if you follow this approach.

From Page_Load to One_Method and from One_Method to Another_Method

Hey I make one more question with my full code because I am really stuck in this point.
When page loads a panel is filled with Book Categories taken from a database. This Categories are linkbuttons too. When I click one category a table is created below with all books on that category.
In that table the first cell is filled with Book's Title that is Linkbutton too.
I just want when I click i that Book'S Title linkbutton to fire the book_Details functions
so that the page now will show only the book I chose.
Instead of that whenever I click books'title linkbutton page loads again from 0.
The markup is:
<asp:Content ID="Content3" ContentPlaceHolderID="MainContent" runat="server">
<div style="position: relative; top: 5%; left: 5%;">
<asp:Panel ID="MyPanel" runat="server"></asp:Panel>
</div>
<asp:MultiView ID="MultiView2" runat="server">
<asp:View ID="View1" runat="server">
<div style="overflow: auto; height: 400px;">
<asp:Table ID="ProductTBL" runat="server" BorderColor="Black" BorderStyle="Double" CellPadding="5" CellSpacing="5" BorderWidth="1px">
</asp:Table>
</div>
</asp:View>
<asp:View ID="View2" runat="server">
<asp:Table ID="detail_TBL" runat="server" BorderColor="Black" BorderStyle="Double" CellPadding="5" CellSpacing="5" BorderWidth="1px"></asp:Table>
</asp:View>
</asp:MultiView>
</asp:Content>
And the code-behind is:
protected void Page_Load(object sender, EventArgs e)
{
String conString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source =" +
Server.MapPath("~/e-bookstoredb.accdb");
using (OleDbConnection connection = new OleDbConnection(conString))
{
connection.Open();
ыtring query = "SELECT * FROM category";
using (OleDbCommand cmd = new OleDbCommand(query, connection))
{
OleDbDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
string literal = (string)reader["Name"];
LinkButton lnk_button = new LinkButton();
lnk_button.Text = literal;
lnk_button.ID = "cat_B" + reader["ID"].ToString();
lnk_button.CommandArgument = reader["ID"].ToString();
lnk_button.CommandName = reader["ID"].ToString();
lnk_button.Command += new CommandEventHandler(books_Show);
MyPanel.Controls.Add(lnk_button);
MyPanel.Controls.Add(new LiteralControl("</br>"));
}
reader.Close();
}
connection.Close();
}
}
protected void books_Show(object sender, EventArgs e)
{
LinkButton lnk = sender as LinkButton;
string cat = lnk.CommandArgument;
MultiView2.ActiveViewIndex = 0;
string ConStr = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source =" + Server.MapPath("~/e-bookstoredb.accdb");
using (OleDbConnection con = new OleDbConnection(ConStr))
{
con.Open();
string query = "SELECT * FROM product WHERE category = #cat";
using (OleDbCommand cmd = new OleDbCommand(query, con))
{
cmd.Parameters.AddWithValue("#cat", cat);
OleDbDataReader reader = cmd.ExecuteReader();
TableCell cell;
TableRow row = new TableRow();
TableCell titleCell = new TableCell();
titleCell.Text = "Τίτλος";
TableCell desCell = new TableCell();
desCell.Text = "Περιγραφή";
TableCell priceCell = new TableCell();
priceCell.Text = "Τιμή";
row.Cells.Add(titleCell);
row.Cells.Add(desCell);
row.Cells.Add(priceCell);
ProductTBL.Rows.Add(row);
LinkButton book_button;
while (reader.Read())
{
book_button = new LinkButton();
book_button.ID = "book" + reader["ID"].ToString();
book_button.Text = (string)reader["Title"];
book_button.CommandArgument = (string) reader["Title"];
book_button.CommandName = "cmd" + reader["ID"].ToString();
book_button.Command += new CommandEventHandler(book_Details);
row = new TableRow();
cell = new TableCell();
cell.Controls.Add(book_button);
row.Cells.Add(cell);
cell = new TableCell();
cell.Text = (string)reader["Description"];
row.Cells.Add(cell);
cell = new TableCell();
cell.Text = reader["price"].ToString()+"€";
row.Cells.Add(cell);
ProductTBL.Rows.Add(row);
}
reader.Close();
}
con.Close();
}
}
protected void book_Details(object sender, EventArgs e)
{
MultiView2.ActiveViewIndex = 1;
LinkButton lnk = sender as LinkButton;
String bookTitle = lnk.CommandArgument;
//...And then I just create a table to show only the book user selected
//...this table gets filled buy this query = " SELECT * FROM product WHERE Title=#bookTitle
}

You must wrap your code within Page_Load with if(!IsPostBack) as shown below. This is because according to ASP.Net page lifecycle Page_Load fires first and control events firs after that.
So, whenever you click your LinkButtons the server first calls the Page_Load and then it calls LinkButton's click event.
So, it's a good idea to wrap your Page_Load code where you only wants to execute once during Page_Load like this.
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
// Your Page_Load logic goes here
}
}
According to MSDN the definition for IsPostBack is
Gets a value that indicates whether the page is being rendered for the
first time or is being loaded in response to a postback.
true if the page is being loaded in response to a client postback;
otherwise, false.
Hope this helped!

How add control programmatically in gridview template?

I want add control label in my gridview, is it possible add with datatable?
here my code:
<asp:GridView ID="reportScheduleDetailsGridView"
runat="server"
AutoGenerateColumns="False">
</asp:GridView>
I try use tag html span, but it not render:
string queryString = #"SELECT * FROM [table1]";
SqlCommand cmd = new SqlCommand(queryString, connOkto);
using (SqlDataReader sdrMaster = cmd.ExecuteReader())
{
while (sdrMaster.Read())
{
DataRow rows = dataTable.NewRow();
rows[0] = sdrMaster["name"].ToString();
for (var x = 1; x < maxCol; x++)
{
queryString = #"SELECT * FROM table2";
cmd = new SqlCommand(queryString, connOkto);
using (SqlDataReader sdrRev = cmd.ExecuteReader())
{
while (sdrRev.Read())
{
blok = "<span></span>";
no = (int)Int16.Parse(sdrRev["no"].ToString());
}
}
rows[x] = blok;
if (no > 1)
{
no--;
}
else
{
blok = "";
}
}
dataTable.Rows.Add(rows);
} }
I don't know, how can add control asp in gridview, like label.
Please help, thanks.

One way to add controls is using OnRowDataBound event of GridView. Add a placeHolder to say, inside <ItemTemplate> of your grid view.
<asp:GridView ID="EmpGridView" OnRowDataBound="EmpGridView_RowDataBound"
<ItemTemplate>
<asp:PlaceHolder ID="placeholder1" runat="server"></asp:PlaceHolder>
</ItemTemplate>
...></asp:GridView>
Ang your code behind file will have:
protected void EmpGridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
// Create a label control
Label lbl = new Label();
lbl.Text="MyDynamic Label";
lbl.ID="lbl1"; // use ID values you prefer
// lets create one more control for example
LinkButton btnlink = new LinkButton();
btnlink.Text = "Delete";
btnlink.ID = "btnDelete";
linkb.Click += new EventHandler(btnlink_Click);
// add the controls to your placeholder inside <ItemTemplate>
PlaceHolder phld = e.Row.FindControl("Placeholder1") as PlaceHolder;
phld.Controls.Add(btnlink);
phld.Controls.Add(lbl);
//code to add the control to only a specific COLUMN/ Cell
e.Row.Cells[1].Controls.Add(btnlink); // adding to 2nd Column
// adding to last column..
e.Row.Cells[EmpGridView.Columns.Count - 1].Controls.Add(btnlink);
}
}
Hope this various ways of adding controls to Templates as well as in a cell of GridView helps you.

How do I pagenate multiple gridviews on the same page?

I am creating an asp.net / C# application with 2 pages.
The JavaScript on 1stPage.aspx will pass two parameters to the second page:
2ndPage.aspx?Paramter1=abc&Paramter2=xyz
2ndPage.aspx will fire a query to a SQL database and dynamically create a gridview.
I create 5 different gridviews on the same page dynamically with different IDs.
I want to pagenate gridview.
When I try to paginate, there is no change on the last 4 grids. Only pagination of first gridview is works properly.
I have tried to cache the dataview, but nothing seems to work.
C# CODE:
protected void Page_Load(Object Src, EventArgs E)
{
if (!IsPostBack)
{
string Param1= Page.Request.QueryString["Paramter1"];
string Param1 = Page.Request.QueryString["Paramter2"];
SqlDataAdapter cmdldata = new SqlDataAdapter("" + Param1 + " " + Param1, sqlconn);
DataView dataview_ldata;
GridView gv = new GridView();
ph.Controls.Add(gv);
gv.ID = "grid" + param1;
gv.AutoGenerateColumns = true;
gv.ShowFooter = false;
gv.CellPadding = 2;
gv.CellSpacing = 0;
gv.Font.Size = 11;
gv.EnableViewState = true;
gv.AllowPaging = true;
gv.PageSize = 10;
gv.RowStyle.Wrap = false;
gv.HeaderStyle.Wrap = false;
gv.PageIndexChanging += new GridViewPageEventHandler(gv_PageIndexChanging);
DataSet dsldata;
dsldata = new DataSet();
cmdldata.Fill(dsldata);
dataview_ldata = dsldata.Tables[0].DefaultView;
gv.DataSource = dataview_ldata;
gv.DataBind();
Cache["data"] = dataview_ldata;
ph.DataBind();
}//end of if IsPostBack
}//end of pageload
void gv_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
GridView gv = (GridView)sender;
gv.PageIndex = e.NewPageIndex;
gv.DataSource = (DataView)Cache["data"];
gv.DataBind();
}
HTML CODE:
<form id="form1" runat="server">
<div>
<asp:PlaceHolder id="ph" runat="server" />
</div>
</form>