Develop Reference

get selected value by drop down list in a repeater by CommandArgument of link button

I have a repeater that in it has one dropdown list and one linkbutton.
I want to get the selected value of the dropdown list by CommandArgument in linkbutton, but it just knows default value of dropdown list.
My code :
<asp:Repeater runat="server" ID="Repeater1" OnItemDataBound="Page_Load2"OnItemCommand="list_ItemCommand" >
<ItemTemplate>
<asp:DropDownList ID="dlPricelist" CssClass="width100darsad dropdownlist" runat="server" AutoPostBack="true" ViewStateMode="Enabled" >
</asp:DropDownList>
<asp:LinkButton ID="btnAddToCart" runat="server" class="btn btn-success btnAddtoCardSinglepage" CommandArgument='<%#Eval("id") %>' CommandName="addtocard">اضافه به سبد خرید</asp:LinkButton>
<asp:Label ID="xxxxxx" runat="server" Text="Label"></asp:Label>
</ItemTemplate>
</asp:Repeater>
Code behind:
protected void Page_Load2(object sender, RepeaterItemEventArgs e)
{
if (!IsPostBack)
{
string id = Request.QueryString["id"].ToString();
DataSet dsselectcategory = BLLTour.left3join(id.Trim().ToString());
var dlPricelist = (DropDownList)e.Item.FindControl("dlPricelist");
dlPricelist.DataSource = dsselectcategory.Tables[0];
dlPricelist.DataTextField = "pricelistPrice";
dlPricelist.DataValueField = "priceid";
dlPricelist.DataBind();
}
}
protected void list_ItemCommand(object source, RepeaterCommandEventArgs e)
{
if (e.CommandName == "addtocard")
{
foreach (RepeaterItem dataItem in Repeater1.Items)
{
Label xxxxxx = (Label)e.Item.FindControl("xxxxxx");
LinkButton btnAddToCart = (LinkButton)e.Item.FindControl("btnAddToCart");
xxxxxx.Text = ((DropDownList)dataItem.FindControl("dlPricelist")).SelectedItem.Text; //No error
}
}
}
I don't know how I should fix it.

You are using very old technology to show data that's not appropriate.
But if you are serious to use it, you must use FindControll method in ItemTemplate of your repeater control. You should find dropdownlist first, and then cast it to a object to be able to use it's value.

Dynamically give Id to button, Commandargument send value

Here is my part of Shop.aspx code:
<% foreach(var item in items){ %>
...
<asp:Button id="btnBuy" runat="server" class="btn" Text="Buy" OnClick ="btnBuy_Click" CommandArgument='<%#Eval("item.id") %>' />
<% } %>
I've got a loop where I create few buttons to my shopping items, and I need them to have id of my item
protected void btnBuy_Click(object sender, EventArgs e)
{
int itemId = Convert.ToInt32(btnBuy.CommandArgument);
}
On click i need to have id of the item/button clicked, to save them later in my database.
Problem -
When i click on button btnbuy.CommandArgument is "".

It's wrong: you wrote c#in asp style. You have to use a Repeater and then you can manage ItemCommand for every button click.
Aspx
<asp:Repeater ID="myRepeater" runat="server" OnItemCommand="myRepeater_ItemCommand">
<ItemTemplate>
<asp:Label id="myLbl" runat="server" Text='<%# ((Item)(Container.DataItem)).ProductName %>'/>
<asp:Button id="btnBuy" runat="server" CssClass="btn" Text="Buy" CommandName="Click" CommandArgument='<%# ((Item)(Container.DataItem)).ProductId %>' />
</ItemTemplate>
</asp:Repeater>
c# (eg. OnLoad)
List<Item> myCollection = ...; // get list of items
myRepeater.DataSource = myCollection;
myRepeater.DataBind();
...
protected void myRepeater_ItemCommand(Object sender, RepeaterCommandEventArgs e)
{
if(e.CommandName == "Click")
{
int idRecord = Convert.ToInt32(e.CommandArgument);
// do something using idRecord or
// get sender properties: ((Button)e.CommandSource).Text
}
}

findcontrol in listview

I want to use FindControl to find the value of the HiddenField i.e hfBlogID. I want to find the value on a ButtonClick
<asp:ListView ID="lvArticle" runat="server">
<LayoutTemplate>
<div runat="server" id="itemPlaceHolder">
</div>
</LayoutTemplate>
<ItemTemplate>
<asp:HiddenField ID="hfBlogID" Value='<%#Eval("BlogID")%>' runat="server" />
<p>
<%#Eval("BlogTitle")%></p>
<p>
<%#Eval("BlogDetails")%></p>
</ItemTemplate>
</asp:ListView>

In order to determine the correct row index you should place your button inside of your ListView.ItemTemplate and handle the ListView.ItemCommand event.
In order to implement this approach you would have to change your code as follows:
<asp:ListView ID="lvArticle" runat="server" OnItemCommand="lv_ItemCommand">
..
<ItemTemplate>
<asp:HiddenField ID="hfBlogID" Value='<%#Eval("BlogID")%>' runat="server" />
<p>
<%#Eval("BlogTitle")%></p>
<p>
<%#Eval("BlogDetails")%></p>
<asp:Button runat="server" CommandName="find" CommandArgument='<%# Eval("yourIDField") %>' />
</ItemTemplate>
...
In code behind:
protected void lv_ItemCommand(object sender, ListViewCommandEventArgs e)
{
switch (e.CommandName)
{
case "find":
var hidden = e.Item.FindControl("your hidden id") as HiddenField;
break;
}
}
If your button is not inside your ListView, then you would need a way to identify the row you want to extract the hidden value from.
For example, if you allow to select a row in your ListView then you could get the hidden value from the selected row as follows:
protected void find_Click(object sender, EventArgs e)
{
var hidden = this.lv.Items[this.lv.SelectedIndex].FindControl("your hidden ID") as HiddenField;
}

If the button is in the same item template then use ItemCommand event handler and in that handler you can fetch the hidden field directly.
If the button is outside of list view then you need to get the index of item whose hidden field'd value you want to get.

you can use if button is in your listview
var control = (HiddenField)e.Item.FindControl("hfBlogID");
or if button is not in your listvew
var contorl = (HiddenField)this.lvArticle.Items[this.lvArticle.SelectedIndex].FindControl("hfBlogID");

Here you can access the hidden field for each item:
protected void Button1_Click(object sender,EventArgs e)
{
foreach(ListViewDataItem item in lvArticle.Items)
{
HiddenField hf=(HiddenField)item.FindControl("hfBlogID");
}
}
if you have index of item already then you can get it directly like this
HiddenField hf=(HiddenField)lvArticle.Items[index].FindControl("hfBlogID");
Hope this will help..

how to find control of dropdownlist inside a datalist

I have a DataList and inside it I have a DropDownList:
<asp:DataList ID="dlconfigureItem" runat="server">
<ItemTemplate>
<asp:DropDownList CssClass="config-select" ID="ddlitem runat="server"></asp:DropDownList>
</ItemTemplate>
</asp:DataList>
How can I get selectedindexchanged event of DropDownList on the server side? I tried this:
public void ddlitem_selectedindexchanged (object sender, EventArgs e)
{
}
but it is not working.

You have defined the server side method:
public void ddlitem_selectedindexchanged (object sender, EventArgs e)
{
}
but you have not told client side that there is an event for you, so in html code tell it like:
onselectedindexchanged="ddlitem_selectedindexchanged"
and also set AutoPostBack property to true.

From the SelectedIndexChanged event the easiest is to cast the sender to the DropDownList
var ddl = (DropDownList)sender;
The sender is always the control that is the source of the event.
For the sake of completeness, from ItemDataBound of the DataList:
protected void dlconfigureItem_ItemDataBound(object sender, DataListItemEventArgs e)
{
DropDownList ddlitem = e.Item.FindControl("ddlitem") as DropDownList;
if (ddlitem != null)
{
// ...
}
}
Edit: Have you forgotten to register the event?
<asp:DropDownList CssClass="config-select"
ID="ddlitem"
OnSelectedIndexChanged="ddlitem_selectedindexchanged"
runat="server">
</asp:DropDownList>
Note that you should not bind your DataList to it's DataSource on postbacks, otherwise events are not triggered. So check for the IsPostBack property of the page.
For example in page_load:
if(!IsPostBack)BindDataList();

Register the event and set AutoPostBack="true"
<asp:DropDownList CssClass="config-select"
ID="ddlitem"
AutoPostBack="true"
OnSelectedIndexChanged="ddlitem_selectedindexchanged"
runat="server">
</asp:DropDownList>
event (on selected index change you can get the selected value)
protected void ddlCategory_SelectedIndexChanged(object sender, EventArgs e)
{
var ddlList = (DropDownList)sender;
string selectedValue = ((DropDownList)ddlList.NamingContainer.FindControl("ddlitem")).SelectedValue;
}

Not sure if you can't get the selected item on the server or you can't find the way to handle the event. In case your problem is with the event handling, try this
<asp:DataList ID="dlconfigureItem" runat="server">
<ItemTemplate>
<asp:DropDownList CssClass="config-select" ID="ddlitem"
OnSelectedIndexChanged="ddlitem_selectedindexchanged"
AutoPostBack="true" runat="server"></asp:DropDownList>
</ItemTemplate>
</asp:DataList>

Accesing a CheckBox that's inside a Repeater

In my repeater's ItemTemplate I've a CheckBox and a disabled TextBox, I need to implement this idea: TextBox only gets enabled if the the CheckBox is checked .. so I set the CheckBox AutoPostBack to true and I tried to put this code in ItemDataBound. but I can't find my control which is weird because I use the same code but in loop "MyRptr.Item[i].FindControl...." and it works! .. I don't want to loop through all the Items, I just wish If I can know the Item number or location in which the CheckBox was created. and I've also tried to create an event handles for the CheckBox's CheckedChanged event but I can't find the CheckBox either!
protected void MyRptr_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
CheckBox ChkBx = e.Item.FindControl("IsSelected_ChkBx") as CheckBox;
if (ChkBx.Checked == true)
{
TextBox TxtBx = e.Item.FindControl("Value_TxtBx") as TextBox;
TxtBx.Enabled = true;
}
}
<asp:Repeater ID="MyRptr" runat="server"
onitemdatabound="MyRptr_ItemDataBound">
<ItemTemplate>
<asp:CheckBox ID="IsSelected_ChkBx" runat="server" Text='<%# Eval("Item") %>' AutoPostBack="True" OnCheckedChanged="IsSelected_ChkBx_CheckedChanged" />
<asp:TextBox ID="Value_TxtBx" runat="server" Enabled="false"></asp:TextBox>
<asp:HiddenField ID="ID_HdnFld" runat="server" Value='<%# Eval("ID") %>' />
</ItemTemplate>
<SeparatorTemplate>
<br></br>
</SeparatorTemplate>
</asp:Repeater>
So basically I need a clean and simple way to implement my logic and If I could get an explanation for what's happening it would be great, so any ideas =) ?

You can find your textbox as follow, but I think its better use the jQuery instead of server-side event
protected void IsSelected_ChkBx_CheckedChanged(object sender, EventArgs e)
{
var ch = (CheckBox)sender;
var txt = ch.Parent.FindControl("Value_TxtBx") as TextBox;
}