Develop Reference

Hide Imagebutton from ASP.NET onclick

I'am trying to hide/show the edit/save button in a ASP.NET Template.
so i want the edit button too show when no row is selected, and then hide it on click and then make the save button visable instead.
How do I access and update the attribute?
The solution ive tried just gives me "Null"
what i have:
<ItemTemplate>
<asp:ImageButton ID="ImageButtonEdit" runat="server" CommandName="Edit" ImageUrl="loginstyling/images/Edit.png"/>
<asp:ImageButton ID="ImageButtonUpdate" runat="server" CommandName="Update" ImageUrl="loginstyling/images/Save.png" OnClick="ImageButtonUpdate_Click" Visible="true"/>
<asp:ImageButton ID="ImageButtonDelete" runat="server" CommandName="Delete" ImageUrl="loginstyling/images/Remove.png" visible="false" />
</ItemTemplate>
what ive tried behind:
protected void ImageButtonUpdate_Click(object sender, ImageClickEventArgs e)
{
ImageButton test = (ImageButton)GridView1.FindControl("ImageButtonUpdate");
test.Attributes.Add("Visible", "False");
}

Try if this works:
test.Visible = false;

Try using RowDataBoundEvent for GridView, if it works:
protected void gridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
ImageButton test = (ImageButton)e.Row.FindControl("ImageButtonUpdate");
test.Visible = false;
}
}

Are you sure that the .FindControl("ImageButtonUpdate");returns a valid object?
Since it returns null check this other post FindControl() return null , it seems to be the same problem you have encountered.

how to get image url on click in repeater

i want to get image url on clicking the image from database in repeater
my database contains(id,url)
my repeater code is:
<asp:Repeater runat="server" ID="repeater" >
<ItemTemplate >
<asp:ImageButton runat="server" Width="200px" Height="200px" ImageUrl='<%#Eval("url") %>' OnCommand="Image_Click" CommandName="ImageClick" CommandArgument='<%#Eval("url") %>' />
</ItemTemplate>
</asp:Repeater>
my .cs code is
protected void Image_Click(object sender, CommandEventArgs e)
{
if (e.CommandName == "ImageClick")
{
string a=e.CommandArgument.tostring();
responce.write(a);
}
}

you can do in ImageClick
((ImageButton)sender).ImageUrl
to get the url of the clicked button

Cast sender to ImageButton and read its ImageUrl property.
Also, is there a reason you are using command instead of handling ImageButtons click event?

Both Vladimir and Guigui answers are prefer way of accessing URL of an image button.
If you also want ID value in addition to URL, you can store multiple values into CommandArgument separated by comma.
<asp:ImageButton runat="server"
ImageUrl='<%#Eval("url") %>'
OnCommand="Image_Command"
CommandName="ImageClick"
CommandArgument='<%# Eval("Id")%> + "," + Eval("url") %>' />
protected void Image_Command(object sender, CommandEventArgs e)
{
if (e.CommandName == "ImageClick")
{
string[] commandArgs = e.CommandArgument.ToString()
.Split(',');
string id = commandArgs[0];
string url = commandArgs[1];
}
}

How to fire an event when dropdown inside Repeater changes

I want to do some actions in my database when user change dropdown's selectedIndex.Now I have the following.
<td class="shop-item-qty">
<asp:DropDownList ID="qtyDropDownList" OnSelectedIndexChanged="changeCount" AutoPostBack="true" runat="server"/>
<asp:HiddenField ID="ItemId" runat="server" Value='<%#Eval("GiftVoucher.ID") %>'/>
</td>
All I want is to get my hidden fields value in changeCount method. The problem is that I can't directly get hidden fields value, because this code is in Repeater element. How can I achieve that functionality?

protected void qtyDropDownList_SelectedIndexChanged(object sender, EventArgs e)
{
DropDownList control = (DropDownList)sender;
RepeaterItem rpItem = control.NamingContainer as RepeaterItem;
if (rpItem != null)
{
HiddenField hiddenField = ((HiddenField)rpItem.FindControl("ItemId"));
}
}

You can bind GiftVoucher.ID value to DropDown's custom attribute and skip HiddenField:
<asp:DropDownList runat="server" ID="qtyDropDownList" OnSelectedIndexChanged="changeCount" AutoPostBack="true" data-itemId='<%# Eval("ID") %>' />
protected void changeCount(object sender, EventArgs e)
{
var id = ((DropDownList)sender).Attributes["data-itemId"];
}

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;
}

Disable LinkButton in DataGrid TemplateColumn

I am using Visual Studio 2008 with .NET Framework 3.5. I have a DataGrid with a LinkButton inside a TemplateColumn. I am trying to figure out how to disable the ability to click the LinkButton once it has been clicked. My DataGrid has 6 columns with the LinkButton column displaying years and the others displaying year end data for those years. When a year is clicked the DataGrid displays a breakdown of that year's data on a month by month basis. When the DataGrid is displaying the month by month breakdown I still need the year column to be visible but without the ability to click. I also have a button and a chart that, by default Visibility is set to false, but after a year is selected the Visibility is set to true with the button giving the ability to close out of the month by month breakdown and return to the year end breakdown. I have everything working except the disabling of the LinkButton.
Here is the code for my DataGrid's TemplateColumn:
<asp:TemplateColumn HeaderText="Year End">
<ItemTemplate>
<asp:LinkButton runat="server" ID="lbYear" Text='<%# DataBinder.Eval(Container, "DataItem.year") %>'></asp:LinkButton>
</ItemTemplate>
</asp:TemplateColumn>
I have tried the following:
Attempt 1 using code behind:
protected void Page_Load(object sender, EventArgs e)
{
LinkButton lb = ((LinkButton) FindControl("lbYear"));
lb.Attributes.Add("onClick", "return false;");
}
Attempt 2 using Javascript:
function disableLinkButton() {
var lb = document.getElementById("lbYear");
if (lb.disabled != true) { lb.disabled = true; return true; }
}
else { return false; }
}
<asp:TemplateColumn HeaderText="Year End">
<ItemTemplate>
<asp:LinkButton runat="server" ID="lbYear" OnClientClick="disableLinkButton()" Text='<%# DataBinder.Eval(Container, "DataItem.year") %>'></asp:LinkButton>
</ItemTemplate>
</asp:TemplateColumn>
-- The 3rd attempt was close which did gray out the LinkButtons but did not disable the ability to click them
Attempt 3 using the 'Enabled' property:
<asp:TemplateColumn HeaderText="Year End">
<ItemTemplate>
<asp:LinkButton runat="server" ID="lbYear" Enabled='<%# Convert.ToInt32(DataBinder.Eval(Container.DataItem, "year"))==1?Convert.ToBoolean("True"):Convert.ToBoolean("False") %>' Text='<%# DataBinder.Eval(Container, "DataItem.year") %>'></asp:LinkButton>
</ItemTemplate>
</asp:TemplateColumn>
Some other thoughts I have include using an 'OnClick' event or a 'CommandArgument'. I tried using 'OnClick' and in the code behind simply using:
LinkButton lb = ((LinkButton) FindControl("lbYear");
lb.Enabled = false;
Any help, thoughts, ideas, examples, etc. would be greatly appreciated. Thank you all in advance!
Adjusted Code:
<ItemTemplate>
<asp:LinkButton ID="lbYear" runat="server" OnClick="testClick" Text='<%# DataBinder.Eval(Container, "DataItem.year") %>'></asp:LinkButton>
<a id="MyContrl_lbYear" href="javascript:__doPostBack('MyContrl$lbYear','')" onclick="this.href='#';this.disabled=true;__doPostBack('MyContrl$lbYear','');"></a>
</ItemTemplate>
protected void showChart(object sender, EventArgs e)
{
LinkButton lbYear = ((LinkButton)FindControl("lbYear"));
lbYear.Attributes.Add("onclick", "this.href='#';this.disabled=true;" + Page.ClientScript.GetPostBackEventReference(lbYear, "").ToString());
}

Option 3 and your last approach seem to be the way to go. The problem with LinkButtons is that even by putting Enabled on false, you wont block them from posting back. See: http://weblogs.asp.net/jeffwids/archive/2011/02/14/how-to-disable-an-asp-net-linkbutton-when-clicked.aspx
Therefore you have to do this manually with:
lb.Attributes.Add("onclick", "this.href='#';this.disabled=true;" + Page.ClientScript.GetPostBackEventReference(lb, "").ToString());

Polity, thank you very much for your help, I really appreciate it. I found a different way to go about fixing this issue though.
.ASPX Code:
<TemplateColumn>
<ItemTemplate>
<asp:LinkButton runat="server" OnClick="test" Text='<%# DataBinder.Eval(Container, "DataItem.year") %></asp:LinkButton>
</ItemTemplate>
</TemplateColumn>
.ASPX.CS Code:
protected void test(object sender, EventArgs e)
{
foreach(var y in myDataGrid.Items)
{
LinkButton lb = ((y as TableRow).Cells[1].Controls[1] as LinkButton);
lb.Enabled = false;
}
}