Proper use of FindControl() in GridViews - c#

I've inherited some code, littered with GridView's, and I've noticed the following sorts of references in the OnItemDataBound method:
Label lblSomething = (Label)e.Row.Cells[3].FindControl("lblSomething");
Label lblSomethingElse = (Label)e.Row.Cells[3].FindControl("lblSomethingElse");
The "issue" is that lblSomething and lblSomethingElse aren't actually in the same cell, but they both appear to be working correctly anyway. Simplifying a bit:
<Columns>
<asp:TemplateField runat="server" HeaderText="Online materials available to assign">
<ItemTemplate>
<asp:Label ID="lblThis" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Assign" HeaderStyle-Width="75px">
<ItemTemplate>
<asp:Label ID="lblThat" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Assign" HeaderStyle-Width="75px">
<ItemTemplate>
<asp:Label ID="lblSomething" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Assign" HeaderStyle-Width="75px">
<ItemTemplate>
<asp:Label ID="lblSomethingElse" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>
Is this behavior expected? If it doesn't matter what cell I'm using the FindControl() with, can I safely/reliably simplify with this instead?
Label lblSomething = (Label)e.Row.FindControl("lblSomething");
Label lblSomethingElse = (Label)e.Row.FindControl("lblSomethingElse");
If not, is it reliable to just use Cells[0].FindControl()?
Should I be worried that the cell mismatch is working only by a happy accident, and that I need to fix these cell indexes ASAP, lest everything break?
Or, am I underestimating the power of FindControl()?

After some experimentation, I've found that the following works perfectly fine.
Label lblSomething = (Label)e.Row.FindControl("lblSomething");
Label lblSomethingElse = (Label)e.Row.FindControl("lblSomethingElse");
Whether this is "best practice" is beyond me.
Also, I've removed runat="server" from the first TemplateField in the markup to match the others. It's unnecessary, apparently. (Who knew?)
<Columns>
<asp:TemplateField HeaderText="Online materials available to assign">
<ItemTemplate>
<asp:Label ID="lblThis" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Assign" HeaderStyle-Width="75px">
<ItemTemplate>
<asp:Label ID="lblThat" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Assign" HeaderStyle-Width="75px">
<ItemTemplate>
<asp:Label ID="lblSomething" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Assign" HeaderStyle-Width="75px">
<ItemTemplate>
<asp:Label ID="lblSomethingElse" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>

Label myLabel = e.row.FindControl("myControl") as Label;
if(myLabel !=null)
{
// Do some work
}
I prefer using as for casting.

Related

Change CommandField text dynamically

<asp:BoundField HearderText="Name" Datafield="Name"/>
<asp:CommandField HearderText="Name" SelectText="Go" ShowSelectButton="True"/>
I want that each CommandField takes the data like DataField, so instead of "Go", it would have values like, "Jhon", "Mary"...in each row
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:LinkButton ID="btnSelect" runat="server" CommandName="Select" Text='<%# Eval("Name") %>'></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
This worked for me

How to set GridView EditItemTemplate Textbox to take maximum cell Width?

I have one Gridview with 5 columns including the edit column. When I click Edit I would like the last column EditItemTemplate Textbox 'The_Title' to take up the maximum width of the cell. It never does! (I can shrink the tbTitle with the Width attribute but not increase) I have tried many things including 'GridView1_RowDataBound'. What am I missing.
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
for (int i = 0; i < e.Row.Cells.Count - 1; i++)
{
if (i == 4)
{
e.Row.Cells[i].Attributes.Add("style", "white-space:nowrap;padding:0px;margin:0px;width:500px");
}
}
}
GridView .aspx - only thing on the page no update panel (1 GV and 1 SqlDataSouce).
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="SqlDataSource1" Width="1000px" OnRowEditing="GridView1_RowEditing" OnPreRender="GridView1_PreRender" OnRowDataBound="GridView1_RowDataBound" OnRowUpdated="GridView1_RowUpdated" OnRowUpdating="GridView1_RowUpdating">
<EditRowStyle BackColor="Red" Width="100%" />
<Columns>
<asp:TemplateField ShowHeader="False">
<EditItemTemplate>
<asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="True" CommandName="Update" Text="Update"></asp:LinkButton>
<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"></asp:LinkButton>
</EditItemTemplate>
<ItemTemplate>
<asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="id" InsertVisible="False" SortExpression="id">
<EditItemTemplate>
<asp:Label ID="lblID1" runat="server" Text='<%# Eval("id") %>'></asp:Label>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="lblID2" runat="server" Text='<%# Bind("id") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="The_Source" SortExpression="The_Source">
<EditItemTemplate>
<asp:TextBox ID="tbSrc" runat="server" Text='<%# Bind("The_Source") %>' Width="50px" ></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="lblSrc" runat="server" Text='<%# Bind("The_Source") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Section" SortExpression="Section">
<EditItemTemplate>
<asp:TextBox ID="TextBox4" runat="server" Text='<%# Bind("Section") %>' Width="50px"></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label5" runat="server" Text='<%# Bind("Section") %>' Width="50px"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="The_Title" SortExpression="The_Title" HeaderStyle-Width="500px" HeaderStyle-BackColor="Red">
<EditItemTemplate>
<div style="white-space:nowrap;background-color:blue;text-align:center;padding:0px;margin:0px;">
<asp:TextBox ID="tbTitle" runat="server" Text='<%# Bind("The_Title") %>' Width="500px" style="white-space:nowrap;"></asp:TextBox>
</div>
</EditItemTemplate>
<ItemTemplate >
<asp:Label ID="lblTitle" runat="server" Text='<%# Bind("The_Title") %>' Width="500px"></asp:Label>
</ItemTemplate>
<ControlStyle BackColor="#3399FF" />
</asp:TemplateField>
</Columns>
</asp:GridView>
// Result image
Any clues would be appreciated. Thank You.
Using Browser developer tools, you should be able to inspect the resulting mark-up (HTML) for your text box and tinker with it to see what is causing the size restriction.
IE developer tools (F12) will show you the hierarchical (cascading) order where the width setting is being defined.
Tested your GridView. The TextBox tbTitle is 500 px wide, just as expected. There is probably some bootstrap or other css overwriting the width.
What happens if you add a class for it?
<EditItemTemplate>
<asp:TextBox ID="tbTitle" runat="server" CssClass="fullWidth" Text='<%# Bind("The_Title") %>'></asp:TextBox>
</EditItemTemplate>
.fullWidth {
width: 100% !important;
}
Or set it inline as !important. If that does not work then there is probably something else going on.
<asp:TextBox ID="tbTitle" runat="server" style="width: 100% !important" Text='<%# Bind("The_Title") %>'></asp:TextBox>

Adding order buttons to a GridView

I have an example from this gridview:
<asp:GridView ID="GridView3" runat="server">
<Columns>
<asp:TemplateField HeaderText="ID">
<ItemTemplate>
<asp:Label ID="Label2" runat="server" Text='<%# Eval("id") %>'></asp:Label>
</ItemTemplate>
<ItemStyle></ItemStyle>
</asp:TemplateField>
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Eval("name") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%# Eval("nome")%>'></asp:TextBox>
</EditItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
And I would like to add a button for ordering the data in each column.
Somebody can help me find the best way to do this?
Sorting is built into the GridView control. There is a control Property called AllowSorting, set this to True and you can sort columns by clicking on the header row titles.
There is no need to add extra buttons, even if you want to do some type of special sorting, you'd still Handle the Sorting event and implement your own methods

Conditional HyperLink in GridView?

I have a gridview with a hyperlink:
<asp:GridView ID="gvEmployees" runat="server" AutoGenerateColumns="False"
CssClass="table table-hover table-striped" GridLines="None" >
<Columns>
<asp:TemplateField HeaderText="Name" SortExpression="EmployeName">
<ItemTemplate>
<asp:HyperLink ID="HyperLink1" runat="server"
Text='<%# Bind("EmployeName") %>' ></asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="ID" SortExpression="EmployeID" Visible="False">
<ItemTemplate>
<asp:Label ID="lblID" runat="server" Text='<%# Bind("EmployeID") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
However, it should only appear as a hyperlink if the employeeID is that of the logged in employee.
I can do all that, but what I do not know is how to make the hyperlink look like a Label. It's easy to have it not link anywhere, but I do not know how to make it look like a label.
Thanks
I believe if you set Enabled="false" it does. If it does not, then the only way to do that is put both a HyperLink and Label in the cell, and show the link when appropriate, and the label when appropriate, hiding the other one (which can be easily done in RowDataBound event).

Not able to DataBound the `Style` attribute in GridView

Not able to DataBound the Style attribute
Style='<%# Eval("LeftPadding","padding-left:{0}") %>'
Full Code
<asp:TemplateField HeaderText="Report Item" SortExpression="ReportItem">
<ItemTemplate>
<asp:Label Style='<%# Eval("LeftPadding","padding-left:{0}") %>' ID="lblReportItem"
runat="server" Text='<%# Eval("Caption") %>'></asp:Label>
</ItemTemplate>
<ItemStyle Width="350px" />
</asp:TemplateField>
But I can DataBound some other attributes even not a Standard HTML attribute, like below
<asp:Label StyleTemp='<%# Eval("LeftPadding","padding-left:{0}") %>' ID="lblReportItem"
runat="server" Text='<%# Eval("Caption") %>'></asp:Label>
What is the problem with Style ?
Got Answer :)
<asp:Label Style=<%# string.Format("padding-left:{0}px",Eval("LeftPadding")!=DBNull.Value? Convert.ToString(Eval("LeftPadding")): "0") %>
ID="lblReportItem" runat="server" Text='<%# Eval("Caption") %>'></asp:Label>
Tried by without giving the Single Quotes for the style attribute and used string.Format
Style=<%# string.Format("padding-left:{0}px",Eval("LeftPadding")!=DBNull.Value? Convert.ToString(Eval("LeftPadding")): "0") %>

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