ASP.NET - Finding Label Control in a GridView - asp.net

I'm having a problem trying to find a label control that is inside a GridView.
Please see my codes below:
<asp:GridView ID="MyGridView" runat="server">
<Columns>
<asp:TemplateField HeaderText="Date">
<ItemTemplate>
<asp:TextBox runat="server" ID="txtDate" MaxLength="10" Width="70" />
<asp:ImageButton ID="imgScoreDate" runat="server" ImageUrl="~/images/calendar.gif" />
<ajaxtoolkit:CalendarExtender ID="txtDate_CalendarExtender" runat="server" Enabled="True" Format="MM/dd/yyyy" TargetControlID="txtDate" PopupButtonID="imgDate" />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:Label ID="lblName" runat="server"/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
And here is my .cs file:
protected void LoadGridView()
{
//Do something else
foreach (GridViewRow row in MyGridView.Rows)
{
//Tried A
System.Web.UI.WebControls.Label lblName = row.FindControl("lblName") as System.Web.UI.WebControls.Label;
lblName.Text = "Name";
//Tried B
((System.Web.UI.WebControls.Label)row.FindControl("lblName")).Text = "Name";
}
}
I debug this code and it seems to work fine because my breakpoint is being hit each time the debugger runs. It even loops through my foreach block the same count as to how many rows my GridView has.
But I don't understand why my lblName control doesn't get the "Name" text as a value? Am I missing anything here? I tried both //Tried A and //Tried B methods but they both doesn't update my label's text.
Any help would be appreciated!
Thanks! Cheers!

You want to call LoadGridView inside PreRender. Basically, you want to call it after GridView is bound with data.
protected void Page_PreRender(object sender, EventArgs e)
{
LoadGridView();
}
Look at PreRender event of ASP.NET Page Life Cycle.

On your gridview add:
<asp:GridView OnRowDataBound="MyGridView_RowDataBound" ... />
Then define MyGridView_RowDataBound:
void CustomersGridView_RowDataBound(Object sender, GridViewRowEventArgs e)
{
Label l = (Label) e.Row.FindControl("lblName");
}
What I think is happening is the control is not recreated server side in its current spot.

try this
on .aspx page
<asp:GridView ID="MyGridView" runat="server"
onrowdatabound="MyGridView_RowDataBound" .../>
code behind ::
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
LoadGridView();
}
}
void LoadGridView()
{
DataTable dt = new DataTable();
// dt= call ur database method to get data
MyGridView.DataSource = dt;
MyGridView.DataBind();
}
protected void MyGridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
Label lbl_Name = (Label)e.Row.FindControl("lblName");
lbl_Name.Text = "Name";
}
}
cheers!

Related

itemTemplate item id not existing in code behind

I am trying to create textboxes that are equal to the number of rows in grid view (databound from db). here is my markup
<asp:GridView ID="quizGrid" runat="server" CssClass="Grid" AutoGenerateColumns="false">
<Columns>
<asp:BoundField DataField="admissionNO" HeaderText="Admission NO"/>
<asp:BoundField DataField="studentName" HeaderText="Name" />
<asp:TemplateField>
<ItemTemplate>
<asp:Textbox runat="server" ID="marks" > </asp:Textbox>
</ItemTemplate>
</asp:TemplateField>
</Columns>
but when i use the marks in code behind it says
quizGrid_marks_0 does not exists in the current context
what im doing wrong here?
You can't access your textbox like that in code behind file, rather you need to find them in RowDataBound event like this:-
protected void quizGrid_RowDataBound(object sender, GridViewRowEventArgs e)
{
if(e.Row.RowType == DataControlRowType.DataRow)
{
TextBox marks = (TextBox)e.Row.FindControl("marks");
txtMarks.Text = "Test";
}
}
Edit:
Okay, suppose you have a button btnGetData with button click event as btnGetData_Click, then you can find the textbox text by looping through the gridview rows like this:-
protected void btnGetData_Click(object sender, EventArgs e)
{
GridView quizGrid = (GridView)Page.FindControl("quizGrid");
foreach (GridViewRow row in quizGrid.Rows)
{
TextBox marks = (TextBox)row.FindControl("marks");
}
}

How to get Reference to the label in repeater item in code behind

<asp:repeater id="rpt" run="server">
<ItemTemplate>
<asp:LinkButton id="Delete" runat="server" OnCommand="Delete_Command"></asp:linkButton>
<asp:label id="lblMessage" run="server">
</ItemTemplate>
</asp:repeater>
Code Behind:
protected void Delete_Command(object sender, CommandEventArgument e)
{
}
how i get the reference to the "lblMessage" in Delete_Command.
Try this:
protected void Delete_Command(object sender, CommandEventArgs e)
{
LinkButton button = (LinkButton)sender;
Label label = (Label)button.NamingContainer.FindControl("lblMessage");
// do something with the label
}
If you:
Have bound the repeater
Have ViewState enabled
Do not re-bind the repeater earlier in the post back
this should work. If not, please verify that the id of the label is indeed exactly the same as in the ...FindControl("lblMessage");. Also make sure that runat="server" is set on all the controls involved.
Edit: One more thing to check: Search the markup file (the .aspx file) and check if there are any other controls that also use the same event in the code behind. If another control is using the same event handler and that control is not in the repeater, the label will not be found.
means are you want find a lable in Delete_Command event?
in aspx
<asp:Repeater ID="rpt" runat="server">
<ItemTemplate>
<asp:LinkButton ID="Delete" runat="server" OnCommand="Delete_Command"></asp:LinkButton>
<asp:Label ID="lblMessage" run="server">
</ItemTemplate>
</asp:Repeater>
in aspx.cs
protected void Delete_Command(object sender, CommandEventArgs e)
{
foreach (RepeaterItem item in rpt.Items)
{
Label lblMessage = item.FindControl("lblMessage") as Label;
if (lblMessage != null)
{
lblMessage.Text = "";
}
}
}
If You want to make it in your way use following code in
protected void Repeater1_ItemCommand(object source, CommandEventArgs e)
{
(((LinkButton)source).NamingContainer).FindControl("lblName")
}
Another approach.. But something that you can buy
aspx
<asp:Repeater ID="Repeater1" runat="server"
onitemcommand="Repeater1_ItemCommand">
<ItemTemplate>
<asp:Label ID="lblName" runat="server" Text='<%=Eval("Name") %>' ></asp:Label>
<asp:LinkButton runat="server" CommandName="Delete_Command" Text="sd"></asp:LinkButton>
</ItemTemplate>
</asp:Repeater>
.cs
protected void Delete_Command(object sender, CommandEventArgument e)
{
if(e.CommandName != null)// Conditional Check
{
Label label = e.Item.FindControl("lblMessage");
// do something with the label
}
}

Getting row from hyperlink in Gridview

I have a Hyperlink field in a asp.net gridview that runs code behind in an aspx file, like
<asp:GridView ID="gvCoursesList" runat="server">
<Columns>
<asp:BoundField DataField="Course" HeaderText="Course">
</asp:BoundField>
<asp:TemplateField>
<ItemTemplate>
<asp:LinkButton ID="lblSignup" runat="server" Text="Sign Up" OnClick= "lblSignup_Click" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
In my code behind file I have the function:
protected void lblSignup_Click(object sender, EventArgs e)
{
}
How do I retrieve the value of the first column from this function.
I would like to do something like
string course = gvCoursesList.DataKeys[e.RowIndex].Value.ToString();
but it's not working. Any other ideas?
#jishnusaha should be the approach you should take. Here is another alternative: http://forums.asp.net/p/1137287/1821091.aspx
protected void lblSignup_Click(object sender, EventArgs e)
{
LinkButton btn = sender as LinkButton;
GridViewRow row = btn.NamingContainer as GridViewRow;
string course = gvCoursesList.DataKeys[row.RowIndex].Value.ToString();
}
<asp:GridView ID="gvCoursesList" runat="server" OnRowCommand="gvCoursesList_RowCommand">
<Columns>
<asp:BoundField DataField="Course" HeaderText="Course">
</asp:BoundField>
<asp:TemplateField>
<ItemTemplate>
<asp:LinkButton ID="lblSignup" runat="server" Text="Sign Up" CommandName="SignUp" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
protected void gvCoursesList_RowCommand(object sender, GridViewRowCommandEventArgs e)
{
if(e.CommandName=="SignUp")
{
string course = gvCoursesList.DataKeys[e.RowIndex].Value.ToString();
}
}
Use the .cells.text to get the value out:
protected void lblSignup_Click(object sender, EventArgs e)
{
GridViewRow row = gvCoursesList.rows[e.rowindex]
string course = row.cells[cellIndex].text;
}
With thanks to codingbiz. His solution just needed a little tweak as per below.
LinkButton btn = sender as LinkButton;
GridViewRow row = btn.NamingContainer as GridViewRow;
string course = row.Cells[0].Text;

gridview edit requires to click twice

Why is that I need to click the edit link twice, in a gridview control, before my row enters into edit mode?
<asp:ObjectDataSource ID="ods" runat="server" TypeName="Employee"
SelectMethod="GetAll" ></asp:ObjectDataSource>
<asp:GridView ID="GridView1" runat="server" CssClass="styled"
OnRowCommand="gv_RowCommand" DataSourceID="ods"
OnSorting="gv_Sorting" >
<Columns>
...........
</Columns>
<ItemTemplate>
<ItemTemplate>
<div class='actions'>
<asp:Button ID="btnEdit" runat="server" Text=" Edit " ToolTip="Edit Row" CommandName="Edit" CommandArgument='<%# DataBinder.Eval(Container.DataItem,"Id") %>' CausesValidation="False" />
<span style="padding-left:10px"></span>
</div>
</ItemTemplate>
</asp:GridView>
protected override void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
this.ods.SelectParameters[0].DefaultValue = "";
}
}
protected void gv_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName == CRUID.Edit.ToString())
{
this.gv.ShowFooter = false;
}
}
You need to avoid rebinding your gridview on each postback.
If not ispostback then
GridView1.DataSource = dt
GridView1.DataBind()
end if
Otherwise you just overwrite Gridview changes.
Great explanation at this link...
http://www.pcreview.co.uk/forums/gridview-two-clicks-needed-enter-place-editing-t3328887.html
Try handling the RowEditing event to set the EditItem Index:
protected void gv_RowEditing(object sender, GridViewEditEventArgs e)
{
gv.EditIndex = e.NewEditIndex
}
There are some mistakes in your code as i examined. Correct your code as shown below:
<asp:ObjectDataSource ID="ods" runat="server" TypeName="Employee"
SelectMethod="GetAll" ></asp:ObjectDataSource>
<asp:GridView ID="GridView1" runat="server" CssClass="styled"
OnRowCommand="gv_RowCommand" DataSourceID="ods"
OnSorting="gv_Sorting" >
<Columns>
...........
<asp:TemplateField>
<ItemTemplate>
<div class='actions'>
<asp:Button ID="btnEdit" runat="server" Text=" Edit " ToolTip="Edit Row" CommandName="Edit" CommandArgument='<%# DataBinder.Eval(Container.DataItem,"Id") %>' CausesValidation="False" />
<span style="padding-left:10px"></span>
</div>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
protected override void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
this.ods.SelectParameters[0].DefaultValue = "";
}
}
protected void gv_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName == "Edit")
{
this.gv.ShowFooter = false;
}
}
If on using this code the problem does not solve then there may be some problem in your cssclass which you used with your GridView as I have Checked your code on my machine using ObjectDataSource and it works well using edited code.
Also I want to know that what is CRUID in CRUID.Edit.ToString()
and why you used the following line in Page_Load event
this.ods.SelectParameters[0].DefaultValue = "";
as there are no parameter associated with your SelectMethod="GetAll" method used in ObjectDataSource.
May this answer help you.
I guess there is some conflict with the updatepanels on your page..
Try removing all your Update Panels and try again.. It will work for sure.. Mine worked a few seconds ago.. so thought It would be good to share..

GridView Paging Issue

I have a very simple GridView on one of my pages with the following markup on my .aspx page:
<asp:GridView ID="gvNews" runat="server" AutoGenerateColumns="false" AllowPaging="true"
AllowSorting="true" DataKeyNames="NewsID,VersionStamp" OnPageIndexChanging="gvNews_PageIndexChanging"
OnRowCreated="gvNews_RowCreated">
<Columns>
<asp:BoundField HeaderText="News Title" DataField="NewsTitle"
SortExpression="NewsTitle" ReadOnly="true" />
<asp:BoundField HeaderText="News Content" DataField="NewsContent"
SortExpression="NewsContent" ReadOnly="true" />
<asp:BoundField HeaderText="Posted Date" DataField="InsertedDate"
SortExpression="InsertedDate" ReadOnly="True" />
<asp:BoundField HeaderText="InsertedBy" DataField="InsertedBy" />
<asp:TemplateField>
<ItemTemplate>
<asp:LinkButton ID="lbEdit" runat="server" Text="Edit" CommandName="Select" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Below is the code on my .cs page:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
LoadGrid();
}
}
private void LoadGrid()
{
gvNews.DataSource = GetNews();
gvNews.DataBind();
}
protected void gvNews_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
}
protected void gvNews_RowCreated(object sender, GridViewRowEventArgs e)
{
e.Row.Cells[3].Visible = false;
}
On the RowCreated event I am trying to hide the InsertedBy column in the gridview. This code works fine when AllowPaging is set to flase. But when the AllowPaging is set to true I get the following error in the RowCreated event handler:
Specified argument was out of the range of valid values.
Parameter name: index
What could be the reasons for this behavior?
You need to write your code like this:
protected void gvNews_RowCreated(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
e.Row.Cells[3].Visible = false;
}
}
With a GridView there are different types of rows that might get created and they will have different numbers of cells, but the RowCreated event will fire for all rows, so you need to limit your logic to only data rows in this case.
From what you have posted your hard coded value of 3 in the RowCreated event seems like the problem. Enable tracing on the page and see what you get. BTW the pager next->prev links also cause postback and in PageLoad u are only loading grid if its not a postback which it is when u try to go for next page and the row created is fired.

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