In asp I want to add row to my gridview when I read barcode. But when I want to add second row , gridview.datasource = null. So, my first row is removed from gridview in TxtBxBarcode_TextChanged event.
TxtBxBarcode and gridview are in the different update panels.
How can I prevent this "gridview.datasource is null when Postback" ?
I've been looking around and trying a lot of different tactics to solve this issue but basically the senario is this.I have a gridview with a fileUpload in it.I can upload a file perfectly and it writes to the database.The trouble starts when I update a different cell and don't touch the cell with the fileUpload in it,it'll postback a null value to the database.
How can I keep the fileUpload control from sending a null on postback to the database so it won't clear out my entry if there isn't a new one to replace it?Or alternatively,how to I default the value to the old value on postback if nothing was entered through the FileUPload control?
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I have 4 gridviews on a page that get databound with a datatable from sql. So I have created the sort/paging events for each. These were working fine. However now they do not work.
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HTML Declaration:
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I am familiar with populating a gridview with data. I am able to bind the Data pulled from the database into the gridview
gridview.DataSource = myDataTable;
gridview.Databound.
If I write the following code, teh gridview will no longer show the data
gridview.DataSource = null;
gridview.Databound.
My question is , I want to make the same thing with a user control that contain a gridview. when I use the user control in an aspx page, I am able to populate it with data, but when I try to make this code, the Datasource does not show, instead, I see .DV. So I tried this code but then , I do not see DataSource property instead I see DV (DataView), when I put .DV = null, I get an error message that the object is not in existed. any idea how to clear the user control gridview from its data.
I have a GridView inside an UpdatePanel in which there is a TemplateField column. I need to save the value of this column every time a user changes it. The problem is that when the TextChanged event causes a postback, the GridView datasource is set to nothing. I've noticed that this happens every time there's a postback. Why?
Here is the code:
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<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Prova.aspx.vb" Inherits="Prova" %>
I am using a list of objects as a datasource and passing the object into a user control. I use the code outlined below
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When I try to access the object this way, it's null.
Funny thing, I can access the user control and all the control data in the user control, but the object (both in the gridview and passed to the user control) are null.
I have setup my business object to have a create_date and edit_date members both datetime datatypes. My company want to display the create_date and edit_date fields in a gridview for each transaction. The problem i have is that after insterting a record it will have a valid create_date but no edit_date and when displayed in the gridview it defaults to datetime.minvalue (My default). How on earth do i show an empty field in my gridview for a null datetime field in the database?
I am using similar architecture to the Imar Spaanjaars example of a tiered solution. With a few small tweeks it has worked well for me for ages. I am passing a List<Database> to my object datasource which connects to my gridview.
A common problem in repeater controls where you want to display data for update (like a list of user phone numbers that can be updated and submitted back to the database) is where to store the database unique row identifier. So, I created a custom Textbox control that I've added a Data property to. I populate this data property with the unique row id. The problem is that when I post back the list and go through the repeater items the control's data property is null. The custom control looks like this:
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The tag in the repeater looks like this:
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I have a custom checkbox with the same data property and it works fine. I actually put in the same repeater with the textbox control and the checkbox control have the row id on postback but the textbox did not. Is there some limitation on the textbox control that might be causing this.
Page 1: To add a record in to DB. At this page, as per the user requests , few controls will be added to the page from server side code. one of them is checkbox list. and when user is requesting to save data, its going to the DB. Everything is fine upto now.
Page 2: To edit the record which is entered from page no 1. When user requests to edit the record entered at page no 1, i'm redirecting user to this update page, with record id, and generating the required controls to show the values. Now the main problem is :
When page is loading first time, I m creating the required controls and then assigning the values to them to edit. but after that at each postback, the value of datasource of checkboxlist is becoming null, same case is with the label control. but the value of textbox is same, it is not becoming empty at each postback. In code: In code i have created two method to generate controls.
1st is : to create new controls, and to assign values to them
2nd is : to regenerate the controls at each postback, with the same IDs, but not assigning any value here.
I think viewstate will reload the values of respective controls, if IDs are same.
How can I insert into a table, parameter values that are determined by the SelectedRow in a GridView without the " " text in Null cells?
Why does " " appear in the database table and not in a Label.Text on the form?
What is the easiest way to prevent from being inserted into the table from a GridView SelectedRow null cell value?
I am not able to figure out why I am getting the null error at SqlDataSource10.Insert(); I tried running through break points and i checked the Insert statement and it has all the required values .. but I get error saying it cannot insert null into NrNarrativeDays. I am working off a sample at this link..
http://www.aspdotnetfaq.com/Faq/How-to-insert-row-in-GridView-with-SqlDataSource.aspx
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Datasource and Gridview code is below
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I take a gridview on my web form ,In one column i display image & view link.My prob is that when any row has not image then do not show view link.
View 7 Repliesi have a grid view that displays a load of figures, and as there is a lot of zero's in these tables i wondered if it would be possible to just display nothing were there is a "0" ... just to make it look cleaner?
View 13 RepliesI have a Gridview showing the data on one of my tables, and when I try to edit the data in one of the columns after I click update, rather than updating the record with the new value I typed in, the rows become null as in, everything in the row I just edited disappears. This inmediatly makes my application crash because one of the fields in my table (IssueDescription) doesn't allows null values.
This is the code, which is actually 100% auto-generated from when I created the GridView control and specified in the options to implement update, delete, edit options.
<asp:GridView ID="GridView1" runat="server" AllowPaging="True"
AutoGenerateColumns="False" DataKeyNames="ticketNum"
DataSourceID="SqlDataSource1" [code].....
What is making the rows turn into null after the update? I did some research and tried to define the Update behaviour myself using RowUpdating function. After hours of learning how to use it I got it to "work", but because the Update turns everything to null when it updates, the sqlconnection command I use to do the query sends null anyways. I can paste the C# code if you'd like to see it, though I'd rather not use it if the auto-generated by asp above can be fixed instead.
Whenever you turn off the visibility of a column in Gridview, on Edit, the value becomes null because its never bound. The only way I know of stopping this behavoir is to put it in the DataKeyName list. Is there any other way to prevent this? I have quite a few columns that will not be displayed in this "release" but I want there for future extensibility. Also, in some cases these values will be used for calculations but the user should not see them. Is there no toggle property for "non-visible" items to remain "unchanged" or something of the sort?
View 3 RepliesThis problem is driving me nuts. I have labels inside a gridview. When i reference them, i keep getting a null error. This is definatly that it cant find the labels inside the template. below is my code that i am using.
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am using a gridview, which is inside datalist, but whenever I try to serach gridview in datalist it reyurns NULL. I using the following code, bolded line is not able to assign gridview:
amespace DataListXML
I have two columns in my Gridview marked false for the visible property but which are clearly listed in the DataKeyNames that are still getting set to null in my database table on update.
The first one is a column MId# which is a type int. It starts as 0 but on edit is turned into null. The Second is RequireSKU which is also converted to null.
I have a gridview with daatsource from MembershipUserCollection. When my collection doesn't contain any records the gridview just disappears. I want to display the empty gridview indicating no records exist rather than the grid just become invisible.
How to make gridview always visible ?
i am working on a website,As i am new to coding i got a problem in it. It was,I hav a gridview in which i am adding the details about a college, and in that i had a buton ("btnReservation") on clicking it another grid will be appeared in which, i hav to enter the reservation details so, till this step it is working fine, but if i enter one college details and clicking on the btnReservetion the grid is being dispalyed and i am able to enter and save the data, But if i enter the details of another college and clicking on the btnReservation, the rows which i hav already entered in the Reservation grid for the previous record are not being Refreshed and are remaining the same,So now i hav to make the gridview datasource null.
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I'm trying to extend the GridView control to enable sorting and paging for any situation.
When using my control I am fetching data from a database and filling a DataSet with it, then binding the GridView upon every page load. My first question would be, is this the correct approach?
To sort the GridView I am overriding the OnSorting method which stores the sort expression and direction in the ViewState, then creates a DataView and utalises the Sort method to sort the underlying data. It then sets the Data Source to this DataView and rebinds the GridView.
Paging is handled by OnPageIndexChanging which simply sets the PageIndex property and again rebinds the GridView.
My problem is; when any control causes a postback my GridView is no longer sorted, presumably because it is persistently rebound. If I don't rebind it then the GridView is empty on postback since the data isn't automatically stored in the ViewState. I have considered saving the data source in the ViewState but I would assume that this is bad practice for large amounts of data? - also DataViews are not seralisable.
The only solution I can think of currently is to override OnDataBound and sort the data every time. This results in a double sort when paging triggers a postback which seems inefficient. Code illustration of this below,
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I'm looking for the cleanest 'best practice' solution as this is a learning exercise more than anything else.
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but if table is empty i.e. there is no record for Store_no=storeno then it bill_id = (Convert.ToInt32(reader[0]) + 1); give a Null exception.
I want to set bill_id=1 if there is no previous record in table of that particular store number. then How to do this.
i.e. How to check that reader[0] is null
cmd1 = new SqlCommand(" Select Max(Bill_No) From Bill_Record Where Store_no='" + storeno + "'", hookUp);
I am trying to pad for null values in the below code. Anybody know how to fix this error? Conversion from type 'DBNull' to type 'String' is not valid.
Dim dvUserImgPath As Data.DataView = CType(ImgPathDS.Select(DataSourceSelectArguments.Empty), Data.DataView)
Dim drUserImgPath As Data.DataRowView = dvUserImgPath.Item(0)
lblHiddenImgPath.Text = drUserImgPath.Item("ImgPath")
I have a SQLDataSource on an ASP.Net C# page. I want the ability to add a Control Parameter based on a DropDown List that will either display records that are either NULL or Not NULL In a Column. I have the following Code Snippet:
SelectCommand="SELECT [PATID], [LastName], [FirstName], [UIN], [Rate], [Account], [Project], [Supervisor], [HireDate], [Assistantship], [Hourly], [FundingStartDate], [FundingEndDate], [TerminationDate], [Citizenship], [TitleCode], [Email], [Notes],
[SupervisorUpdateEnabled], [SupervisorTargetSemesterCode], [PATCertDate] FROM [PATAccounts] WHERE TerminationDate @Terminated ORDER BY [LastName]"
I have a gridview I create dynamically and one of the columns is a checkbox. I need to set an event handler on this control for checkedchanged. everything appears to work fine except for one thing....even though I can see my WebForm controls they are all null..(even thogh I know they are not) So I basically cant do anythign to the controls in the event handler. Here is teh code I use to create teh dynamic column in the gridview.
EtscUtilsUI.ALMSSECSRV.EALMSAppRoles ealmsapprole =
new EtscUtils.EtscUtilsUI.ALMSSECSRV.EALMSAppRoles();//Thsi
is the webform code behind partial class.
CheckBox chk =
new
CheckBox();
chk.ID = _columnName;
chk.DataBinding += new
EventHandler(chk_DataBinding);
//Attaches the data binding event.
chk.AutoPostBack = true;
chk.CheckedChanged += new
EventHandler(ealmsapprole.Dyn_CheckChanged);
container.Controls.Add(chk);
chk.Enabled = true;
This is the code for the event Handler
internal
void Dyn_CheckChanged(object sender,
EventArgs e)
{
string err =
"";
try
{
if (lblAppID.Text !=
"")
}
that label come back as null event though a previous event set its value successfully if I try to reference the gridview itself I get the error Object reference not set to an instance of an object.