Forms Data Controls :: Rowdatabound Event Of A Gridview Loses Its Value While Editing?
Feb 5, 2011
I have a Gridview with edit and update feature enabled. It displays the data correctly but when I click on the Edit linkbutton(to edit the data), I get the error "Object reference not set to an instance of an object".
I tried debugging and found that the row which I click (say editindex is 1) loses its value. I could identify this while debugging the code, when the code flow moves to the rowdatabound event, the label (or for that matter any control in the rowdatabound event) shows a null value and eventually errors out.
I am unable to figure out as to why the control specified in the rowdatabound event loses its value when editing. Note: The lost valueow data is the one which I tried editing.
I am attaching the code which I have written for the rowdatabound event.
why the gridview RowDataBound event fires during a select command. I only expect it to run when the gridview is being populated with data. Is there some way to stop it from running when the select command is triggered?
When a Gridview row is in edit, I need to default an empty textbox to today's date. I am close, but the defaulted date is is not saved to the database. I can key in the date and the date is displayed and saved to the database. Even more interesting:
1. The date is defaulted to - 5/17/2010 2. If I erase the month and key the "5" back in the data is not saved. 3. If I erase the month and then change the month to "6", the data is saved to the database. If any value is changed in the date the save works.
I use linq query as below and bind it to listview. I have 2 label control (name,remain).I want to check in code behind if p.count<200 then remain ="Sample text1"if price <300 then "sample text2".I know that I could do it before linq in gridview RowDataBound event
Dim prod= From p In db.products _ Select New With {p.name p.category, p.count} postlist.DataSource = prod postlist.DataBind()
I have a very simple asp.net page, just some buttons and one GridView on it. The logic is a user click the QUery button,then the button click event was trigured to populate the gridview with data queried from database via LINQ. for a user friendly interface, in RowDataBound event, I visit every row, change a boolean value into checkbox represention. But it seem that the RowDataBound run twice, because the checkboxs were inserted twice for every row in one cell. so why? the source code snippet as follow:
Why wasn't my GridView's RowDataBound event fired? I have a masterpage on whick i have a query button, and I have a content page on which i have a customized GridView(named cgvEmployees,derived from GridView). The logic is when user click the button, the button click event triggered that search the underlying database and populate the GridView.
Everything runs great except that RowDataBound event isn't triggered. Because I have to change some cells' representations in RowDataBound event handler. I have surfed so much pages to find the answer but failed. Below is what i have already done:
1. set the autoeventwireup to true; 2. i have a cgvEmployees.bind() sentence in the button click event handler; 3. i have OnRowDataBound="cgvEmployees_OnRowDataBound" in the content page GridView tag attribute
by the way, the database query is coded by Linq Dynamic Query (please google 'dynamic Linq').
void Master_QueryButton_Click(object sender, EventArgs e) { RetiredEmployeeDataContext db = new RetiredEmployeeDataContext(); NameValueCollection nvcQueryKeyValue = getNVCQueryKeyValue(); Expression<Func<RetiredEmployee, bool>> searchPredicate = getLambdaExpr(nvcQueryKeyValue); IQueryable<RetiredEmployee> retireds = db.RetiredEmployees; Expression expr = Expression.Call(typeof(Queryable), "Where", new Type[] { typeof(RetiredEmployee) }, Expression.Constant(retireds), searchPredicate); IQueryable<RetiredEmployee> query = db.RetiredEmployees.AsQueryable().Provider.CreateQuery<RetiredEmployee>(expr); List<RetiredEmployee> employeeList = new List<RetiredEmployee>(query); List<RetiredEmployeeEO> employees = new List<RetiredEmployeeEO>(); foreach (RetiredEmployee employee in employeeList) { RetiredEmployeeEO employeeEO = new RetiredEmployeeEO(); employeeEO.MapEntityToProperties(employee); employees.Add(employeeEO); } cgvEmployees1.ListClassName = typeof(RetiredEmployeeEOList).AssemblyQualifiedName; cgvEmployees1.LoadMethodName = "LoadFromQuery"; cgvEmployees1.LoadMethodParameters.Clear(); cgvEmployees1.LoadMethodParameters.Add(employees); cgvEmployees1.DataBind(); } protected void cgvEmployees1_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.DataRow) { //Add the edit link to the action column. HyperLink editLink = new HyperLink(); if (((BasePage)this.Page).ReadOnly) { editLink.Text = "View"; } else { editLink.Text = "Edit"; } editLink.NavigateUrl = "employee.aspx" + EncryptQueryString("id=" + ((RetiredEmployeeEO)e.Row.DataItem).ID.ToString()); if(e.Row.Cells[0].Controls.Count==0) e.Row.Cells[0].Controls.Add(editLink); //Add checkbox to display the isactive field. CheckBox chkActive = new CheckBox(); chkActive.Checked = ((RetiredEmployeeEO)e.Row.DataItem).liveOrDead; chkActive.Enabled = false; if(e.Row.Cells[24].Controls.Count==0) e.Row.Cells[24].Controls.Add(chkActive); if (((RetiredEmployeeEO)e.Row.DataItem).gender.Equals((byte)1)) e.Row.Cells[2].Text = "Male"; else e.Row.Cells[2].Text = "Female"; if (((RetiredEmployeeEO)e.Row.DataItem).retiredOr.Equals((byte)1)) e.Row.Cells[14].Text = "Retired1"; else e.Row.Cells[14].Text = "Retired2"; if (((RetiredEmployeeEO)e.Row.DataItem).birthday.Equals("1753-01-01")) e.Row.Cells[3].Text = ""; if (((RetiredEmployeeEO)e.Row.DataItem).dayToEmployed.Equals("1753-01-01")) e.Row.Cells[6].Text = ""; if (((RetiredEmployeeEO)e.Row.DataItem).dayRetired.Equals("1753-01-01")) e.Row.Cells[7].Text = ""; if (((RetiredEmployeeEO)e.Row.DataItem).dayParty.Equals("1753-01-01")) e.Row.Cells[13].Text = ""; if (((RetiredEmployeeEO)e.Row.DataItem).daytoassign.Equals("1753-01-01")) e.Row.Cells[17].Text = ""; } }
How do I access GridView Page Index in RowDataBound event? I am assigning PageIndex to hyperlink on the gridview, for this I was planning to use "GridView1.PageIndex" in rowdatabound event. Problem is when I got second page in gridview (10 rows per page), the first row in the page shows page index as "0" and from second row it becomes 1. And if I goto third page, the first row in the page shows page index as "1" and from second row it becomes 2.
Can I call a javascript function in the RowDatabound event of the Gridview?
I am currently enabling/disabling buttons in each of my gridview rows based on a status value from the database.I need to fire a javascript function (say alert('current status')) when the status is 0,else dont fire that function.Can I achieve this in the row databound event?
I want to have a total in the gridview footer of the duration of the employees. As the rowdatabound goes through the cycles I can see it reading the correct times from each row but it is not totalling in totalTime and I get 0:00:00 in the footer.
I have a page on which everything is loaded dynamically.
There is a Gridview (AutoGenerateColumns=true) and in the RowDataBound I check every column for a boolean datatype. If found I add a checkbox (autopostback=true) to the cell and register the CheckedChanged event. The problem is, that I only get the CheckedChanged event, if I reload the grid in Page_Load:
I have a Master/Slave GrisViews or some say Parent/Child GridViews.
i want to set my button visible=false in the child gridview if data is not exist.
i try this:
Protected Sub gv_child_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) If e.Row.RowType = DataControlRowType.DataRow Then e.Row.Attributes.Add("onmouseover", "this.style.backgroundColor='#FFC080';") e.Row.Attributes.Add("onmouseout", "this.style.backgroundColor='';") Dim lblitemid As Label = CType(e.Row.Cells(1).Controls(1), Label) Dim lblphoto As Label = CType(e.Row.Cells(11).Controls(1), Label)
[Code]......
but it does not working. the button is still there.
On Row databound i want to show some rows in If and Hide in some rows in else conditon. But it generate an exception that (Index was out of range. Must be non-negative and less than the size of the collection Parameter name: index.
protected void gvHotels_RowDataBound(object sender, GridViewRowEventArgs e) { DataTable dt = new DataTable(); if (e.Row.RowType == DataControlRowType.DataRow)
rowdatabound event is not firing during postback ,What to do?First time pageload I am getting result as expected. When I click checkbox ,which is in grid ,my values which are in other columns get disappeared, that means during postback. How to maintain values in the grid even after postback.note : I did some small manupulation of data during rowdatabound event for the columns which are in the grid.
