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C# GridView FindControl HTML unordered list

I want to find an unordered list inside my GridView so that I can hide it based on a condition. I do not know what to cast the object as however. Using HtmlGenericControl does not seem to work. I receive a Object reference not set to an instance of an object error.
Markup:
<asp:GridView ID="myGV" runat="server">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="myCb" runat="server" Text='Hi'/>
<ul id="myUnorderedList" runat="server" Visible="True">
<li>
<asp:TextBox ID="myTb" runat="server" Width="300" />
</li>
</ul>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
C#:
foreach (GridViewRow row in myGV.Rows)
{
if (Some Condition)
{
//works bc properly casted to CheckBox
((CheckBox) row.FindControl("myCb")).Visible = false;
//Does not work. What to cast this to?
((System.Web.UI.HtmlControls.HtmlGenericControl) row.FindControl("myUnorderedList")).Visible = false;
}
}

System.Web.UI.HtmlControls.HtmlGenericControl is a correct cast for ul.
Besides, you do not even need to cast to HtmlGenericControl, because Visible is a property of System.Web.UI.Control from which all web controls inherited.
You just need the following code -
(row.FindControl("myUnorderedList")).Visible = false;

Stop DropDownList SelectedIndexChanged Event firing on FormView command

I have a dropdown list inside an editItemTemplate. The Dropdownlist onSelectedIndexChanged event fires on change like I want. However it also will fire when I submit the form.
********UPDATE ************
Per Saechel comment below, I started to investigate further. Here it describes it can be done. http://blog.programmingsolution.net/net-windows-application/selectionchangecommitted-and-selectedindexchanged-events-system-nullreferenceexception-while-closing-windows-form/
BUT, I tried it and it didn't even fire the event.
I checked http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.dropdownlist(v=vs.110).aspx and they don't list the event.
My goal is to let the user enter the values as a % of the Total or actual as actual tons and then toggle back and forth. The end value that will be inserted into the DB will be in tons.
I want to either:
a) not fire the "onSelectedIndexChanged" event
b) Some how determine if I am on the same index and have an if statement to skip everything
c) A better way of going about this that I don't know of.
I tried verifying via the ViewState the Dropdown's current index and skip the code if it was the same but couldn't find the value. Maybe help me figure out how to get that value? Searched around and could not find how do do it.
I tried: `var vs = ViewState["ddl_units"].ToString(); and some other variations as I needed to find the control via FindControl
.aspx:
<asp:Panel ID="pnlRecycledMaterialsReceivedForm" runat="server" Visible="false">
<asp:FormView ID="fvAddRecycledMaterialsReceived" runat="server" SkinID="annualReportFormview" EnableViewState="false"
HeaderText="Selected Recycled Materials Received Detail" DataKeyNames="RecycleDetailId" DefaultMode="Insert"
DataSourceID="odsRecycledMaterialsReceivedDetail" OnDataBound="fvAddRecycledMaterialsReceived_DataBound"
OnItemCommand="fvAddRecycledMaterialsReceived_ItemCommand" OnItemInserted="fvAddRecycledMaterialsReceived_ItemInserted"
OnItemUpdated="fvAddRecycledMaterialsReceived_ItemUpdated" OnItemDeleted="fvAddRecycledMaterialsReceived_ItemDeleted">
<EditItemTemplate>
<asp:TextBox ID="tbxRecycledTotalWasteQuantity" runat="server" Text='<%# Bind("TotalWasteQuantity") %>' Width="64px"></asp:TextBox>
<asp:TextBox ID="tbxRecycledWasteCommercialQuantity" runat="server" Text='<%# Bind("CommercialQuantity") %>' Width="64px"></asp:TextBox>
<asp:TextBox ID="tbxRecycledWasteResidentialQuantity" runat="server" Text='<%# Bind("ResidentialQuantity") %>' Width="64px"></asp:TextBox>
<asp:DropDownList ID="ddl_Units" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddl_Units_SelectedIndexChanged">
<asp:ListItem Value="" Text="" Enabled="false" />
<asp:ListItem Text="Tons" Value="1" />
<asp:ListItem Text="Percent" Value="9" />
</asp:DropDownList>
<asp:LinkButton ID="lbtnWasteReceivedUpdate" runat="server" Text="Update" CommandName="Update"
ValidationGroup="RecycledWasteReceivedDetail" Font-Bold="True" />
<asp:LinkButton ID="lbtnWasteReceivedInsertCancel" runat="server" Text="Cancel" CausesValidation="False" CommandName="Cancel" />
</EditItemTemplate>
</asp:FormView>
</asp:Panel>
.cs:
protected void ddl_Units_SelectedIndexChanged(object sender, EventArgs e)
{
TextBox tbxRecycledTotalWasteQuantity = (TextBox)fvAddRecycledMaterialsReceived.FindControl("tbxRecycledTotalWasteQuantity");
TextBox tbxRecycledWasteResidentialQuantity = (TextBox)fvAddRecycledMaterialsReceived.FindControl("tbxRecycledWasteResidentialQuantity");
var d_TotalWasteQuantity = Convert.ToDecimal(tbxRecycledTotalWasteQuantity.Text);
ResidentialQuantity = Convert.ToDecimal(tbxRecycledWasteResidentialQuantity.Text);
DropDownList ddl_units = (DropDownList)fvAddRecycledMaterialsReceived.FindControl("ddl_units");
if (ddl_units.SelectedIndex.ToString() == "2")
{
//2 = percent
//Take tb value and convert to percent
//300/700 * 100
tbxRecycledWasteResidentialQuantity.Text = ((ResidentialQuantity / d_TotalWasteQuantity) * 100).ToString();
//ResidentialQuantity = ResidentialQuantity * (d_TotalWasteQuantity / 100);
}
else
{
//Else 'tons' was chosen. Convert value(%) to tons.
//700 * (43/100) = 301
ResidentialQuantity = d_TotalWasteQuantity * (ResidentialQuantity / 100);
tbxRecycledWasteResidentialQuantity.Text = ResidentialQuantity.ToString();
//tbxRecycledWasteResidentialQuantity.Text = "Tons";
}
}

Try using the SelectionChangeCommitted Event.
This will not trigger on form load but triggers on selectionchange

How to set ImageUrl based on the value of a field in a gridview

I have the following line of code which evaluates whether the value is true or false, if its true it will show an image if its false it shows a different one.
<itemTemplate>
<img alt="" id="Img1"
src='<%# MyAdmin.GetCheckMark((bool)DataBinder.Eval(Container.DataItem, "ShowImg"))%>'
runat="server" /></ItemTemplate>
Can I customize the Eval part in the back end code in c# and then pass a different variable to it for example in C# I want to do
bool ImgFlag = false;
if(Entity.ShowImg == false && Entity.SomethingElse == true)
{
ImgFlag = true;
}
else if(Entity.ShowImg == false && Entity.SomethingElse == false)
{
ImaFlag = false;
}
else
{
ImgFlag = true;
}
And then I want to use ImgFlag instead of ShowImg in my GridView on each row, so ImgFlag will determine which flag to show..
Or is there a better way?
The issue is that that eval depends now on two things.. not one as before.
Thank you

This does the trick
<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<asp:Image runat="server" ImageUrlt='<%#(bool)Eval("bit_field")? "first.jpg":"second.jpg" %>'>
</asp:Image>
</ItemTemplate>
Or this
<asp:TemplateField HeaderText="YourField">
<ItemTemplate>
<asp:ImageButton runat="server" ImageUrl="True.jpg" Visible='<%# (bool)Eval("bit_field") %>' />
<asp:ImageButton runat="server" ImageUrl="False.jpg" Visible='<%# !(bool)Eval("bit_field") %>' />
</ItemTemplate>
Found in this question

Eval actually returns a property, so you can just call it twice for different properties.
Kind of
MyAdmin.GetCheckMark2((bool)DataBinder.Eval(Container.DataItem, "ShowImg"),
(bool)DataBinder.Eval(Container.DataItem, "SomethingElse"));
may help

Get the Current Selected Row of GridView on a button Click

I want to fetch the DataKey of the Selected Row of GridView on button click.

I would Personal do it in a Template Field Like so:
<asp:TemplateField>
<ItemTemplate>
//EDIT: after a comment it is suggested that you pass the RowIndex as the command argument which would provide access to the entire row
<asp:LinkButton ID="btnCopy" runat="server"CausesValidation="False"CommandName="MyCommandButton"CommandArgument='<%# Eval("MyDataKeyOrWhateverIWanteverIWantFromTheBindingSource")%>'>
</ItemTemplate>
</asp:TemplateField>
CodeBehind
protect void MyCommandButton(Object sender,CommandArgument e)
{
int DataKeyOrPK=int32.Parse(e.CommandArgument.ToString());
}
You other option would be:
<asp:gridview id="myGrid" runat="server"
width=100% datakeynames="Myid"
autogeneratecolumns=false
onSelectedIndexChanged="MyEvent">
<asp:templatefield headertext="Choose your dream home">
<itemtemplate>
<asp:linkbutton runat="server" commandname="select" text='<%# Eval ( "Whatever" ) %>' />
</itemtemplate>
</asp:templatefield>
Note the commandname="select" above.
Data-bound controls recognize certain command names and automatically raise and handle the appropriate events for the control. The following command names are recognized:
Cancel, Delete, Edit, Insert, New, Page, Select, Sort and Update. Reference
Codebehind
private void MyEvent(Object sender, EventArgs e)
{
string id = myGrid.SelectedDataKey.Value.ToString();
}

Use the SelectedDataKey property of the GridView:
DataKey currentKey = myGridView.SelectedDataKey;

how to check status of checkboxes in gridview columns on click of button

T have used checkbox column in gridview. On click of a linkbutton, it should be checked that checkboxes in gridview are checked or not. If none check box is checked then it should display alert("Check at leat one check box").

You will have to add some custom Javascript to your page for the client-side alert to show. Here's a method that I've written that works with a GridView called 'GridView1' (this should be the default name if you've just dragged the control onto your ASPX page):
<script type="text/javascript">
function ClientCheck() {
var valid = false;
var gv = document.getElementById("GridView1");
for (var i = 0; i < gv.all.length; i++) {
var node = gv.all[i];
if (node != null && node.type == "checkbox" && node.checked) {
valid = true;
break;
}
}
if (!valid) {
alert("Invalid. Please select a checkbox to continue.");
}
return valid;
}
</script>
You can see that it sets a variable to the GridView control to start with, then iterates through all the children in a for loop. If the child is a checkbox and it is checked, then we set the valid variable to true. If we get to the end of the iteration and no checked checkboxes are found, then valid remains false and we execute the alert.
To link this into your GridView on your ASPX page, first make the button column a TemplateField and surround the LinkButton with your client-side code. If you've used the designer to set up your columns, you can use the "Convert this field into a TemplateField" link in the column editor). Here's an example of the source you'll end up with:
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="ObjectDataSource1">
<Columns>
<asp:TemplateField HeaderText="Button Field" ShowHeader="False">
<ItemTemplate>
<span onclick="return ClientCheck();">
<asp:LinkButton ID="LinkButton1" runat="server" CommandName="IDClick" Text='<%# Eval("YourDataSourceItem") %>'></asp:LinkButton>
</span>
</ItemTemplate>
</asp:TemplateField>
// ...your remaining columns...
Using the TemplateField lets us add any client-side code we like. Here we're adding a span and using onclick to call our ClientCheck method.
If you aren't bothered about the alert, you could achieve your aims by using a CustomValidator control, which executes on the server-side.
I hope this helps.

I found the answer. and its working...
function checkBoxselectedornot()
{
var frm=document.forms['aspnetForm'];
var flag=false;
for(var i=0;i<document.forms[0].length;i++)
{
if(document.forms[0].elements[i].id.indexOf('chkDownloadSelectedEvent')!=-1)
{
if(document.forms[0].elements[i].checked)
{
flag=true
}
}
}
if (flag==true)
{
return true
}else
{
alert('Please select at least one Event.')
return false
}
}
and girdview code is...
<asp:BoundField ItemStyle-Width ="100px" DataField ="EventStartDate" DataFormatString ="{0:g}" HeaderText ="<%$ Resources:stringsRes, ctl_EventList_StartDate %>" SortExpression ="EventStartDate" HtmlEncode ="true" ItemStyle-Wrap ="false" />
<asp:BoundField ItemStyle-Width="100px" DataField="EventDate" DataFormatString="{0:g}" HeaderText="<%$ Resources:stringsRes, ctl_EventList_Date %>" SortExpression="EventDate" HtmlEncode="true" ItemStyle-Wrap="false" />
<asp:ButtonField ItemStyle-Width="150px" ButtonType="Link" DataTextField="EventName" HeaderText="<%$ Resources:stringsRes, ctl_EventList_Event %>" SortExpression="EventName" CommandName="show_details" CausesValidation="false" />
<asp:BoundField DataField="EventLocation" HeaderText="<%$ Resources:stringsRes, ctl_EventList_Location %>" SortExpression="EventLocation" />
<asp:TemplateField HeaderText ="Select">
<ItemTemplate >
<asp:CheckBox ID="chkDownloadSelectedEvent" runat ="server" AutoPostBack ="false" Onclick="eachCheck();"/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
<RowStyle Height="25px" />
<HeaderStyle Height="30px"/>
</asp:GridView>
and there is a link button ....

I havnt used the checkbox in grid view but would you not do a for loop around the columns in gridview and check the state? Myabe add a count and if 0 then alert.

var grid = document.getElementById("gridId"); //Retrieve the grid
var inputs = grid.getElementsByTagName("input"); //Retrieve all the input elements from the grid
var isValid = false;
for (var i=0; i < inputs.length; i += 1) { //Iterate over every input element retrieved
if (inputs[i].type === "checkbox") { //If the current element's type is checkbox, then it is wat we need
if(inputs[i].checked === true) { //If the current checkbox is true, then atleast one checkbox is ticked, so break the loop
isValid = true;
break;
}
}
}
if(!isValid) {
alert('Check at least one checkbox');
}