VS 2008 DataTable.Merge(AnotherDataTable) - RowState Remains Unchanged?
May 25, 2009
I want to compare differences between two tables in my database with identical schemas.
vb.net
DataTable1.Merge(DataTable2)
Dim changedRows As DataTable = DataTable1.GetChanges
'changedRows is always Nothing. Why???
The DataTable1 is updated with rows from DataTable2 correctly. i.e. missing rows are added and datarows that don't match are updated. But the RowState of each row is still unchanged. I need to have the rowstate (added/modified/deleted) so that I can update the database table.
I've got lots of textboxes bound to a Dataset. When I make changes to a textbox with the mouse/keyboard the rowstate becomes changed - and when I do the .EndEdit and update the row it goes to the DB.
I've got some textboxes that get changed in code. When this happens the rowstate remains UNCHANGED. Updates to the DB never occur.If the textbox is changed in code and I also change another textbox in the UI then both changes make it to the DB.
I've verified that the "in-code" changed field in the dataset is actually changed - but the ROWSTATE is still printing as UNCHANGED.Here I'm showing that field 29 has changed to "blank" - but the RowState still is UNCHANGED. Why would changes to the .Text property of a bound control does programatically not change the row state?
Seems a google for this does uncover issues like this - but nothing that's helped me fix it so far - here's one link I can't make sense of[URL]..
I've got my code to delete rows out of the database when the user clicks on the Delete button in my GridView, but the GridView isn't updating to reflect the new data changes.
EDIT 1:Did some stepping through the code and found that e.CommandArgument is not getting a value in grdQuestions_RowCommand
EDIT 1 (Revised):The fact that e.CommandArgument wasn't getting a value was my mistake. I'd changed the way it's value was being assigned without removing the previous method.The code runs through grdQuestions_RowCommand and then goes into grdQuestions_RowDeleting and then executes GetModuleData.I have a feeling that to view changes to the grid, a PostBack might be required, but I've removed all DataBinding to an If Not IsPostBack Then block because the alternative caused problems with the DropDownList whose selection is used as a reference to populate the grid (ddlModules selected the Module whose Questions will display in the grid).
I have a datagridview bound to a datatable via a dataview. The user is allowed to edit cells in the datagridview, thereby editing cells in the datatable. I recently found that if the user editted a cell, then closed the form without ever clicking on a different cell (thereby causing the current cell to commit), the change was vanishing because the editted contents of the cell were not being saved back to the datatable.
This was only happening if the user closed the form. Clicking on any other control on the form also caused the cell changes to commit. After rooting abut in the DGV properties, it appeared that all I needed to do is add the following code to the Form Closing event handler:
If Me.dgvCurrentRedds.IsCurrentCellDirty Then Me.dgvCurrentRedds.CommitEdit(DataGridViewDataErrorContexts.Commit) End If
Sure enough, this caused the change to be registered in the underlying datatable. However, it was then getting obliterated by a different process, so I went looking for the source of that problem, and eventually tracked it down to this:
While the preceding code is causing the datatable to receive the new information, the datarow that has been changed still has the status Unchanged, even though it should have the status Modified since it actually has been modified. The fact that it appears unchanged causes some other code to obliterate the change, but that's irrelevant.
The question is, why is the row status UnChanged when it certainly has been Changed, and is there any sound way to force the row status to update?
when i am iterating through the rows I would like to check rowstate to see if row was added or modified. It says I cant check through an instance and the expression will be ignored..
Dim changes As New DataSet changes = dsRates.GetChanges() Dim count As Integer = 1
I have a spreadsheet that contains details of change requests; one row per request. This information needs to be copied into a Word form for sending off to our customer who then completes the response section. To speed up this process I have written some code that utilises the mail merge feature of Word and merges the relevant info from the spreadsheet into a Word form. This runs from Excel when a button is pressed.The problem comes when I go to save the workbook and exit Excel; it stays running in the background as a process in task manager.
[URL]
I'm fairly sure it has something to do with the merge code itself but my knowledge of VB is enough to grasp what is happening but not why it is happening. If I open the Word doc that has the merge fields in it, then open the spreadsheet that houses the info Excel says the workbook is already open.
Not certain what exactly I am doing wrong here, but I am having problems in setting a new DataTable (for posting back to the database) to the Changes resulting from the Merge proc of 2 DataTables. The code works fine until I attempt to set the ChangesTable --- it always ends up = Nothing.What is strange is that the "preMergeCount" = 0 and the "postMergeCount" = 23, which is EXACTLY how I expect it to be! So I know that the Merge is working correctly.
Dim sqlTable As DataTable = dsMonitoring.Tables("SQL_SRTraps") Dim exlTable As DataTable = dsMonitoring.Tables("Excel_SRTraps") AddHandler sqlTable.RowChanged, AddressOf Row_Changed
I need to marge two datatable with condition. i table data come from local XML Database and another data come from remote sql data if any update made at remote datatable and then marge with local datatable. i wrote a code below :
Public Sub MargeTwoTable() Dim SQL As String = "" Dim RemoteTable As New DataTable Dim LocalTable As DataTable
[code]....
as you see in my code data come from remote database which update date getter then local database . Both table are same and "ID" is primary key. I code is working well. But problem is that when data more then 1000 updated record so this function take too long in loops.
i write a code like : Dim mm() As DataRow = LocalTable.Select("ID = '" & RemoteTable.Rows(i).Item("ID") & "'"). for finding local datatable id row so when data is more then 1000 it take too long because localtable record more than 100000 records. So I need someone help to modify my code what the best way to write the code.
The problem is I want merge duplicate serial_no into one row which the value of testong adding to new column. I have tried many ways, but I can't find the solution. Here is my code behind :
My code got an error at messagebox.show at messagebox said System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object"What is wrong? (dt1 and dt2 are all ok. They are have only one columnd: ID)
i create a Class to update data from remote sql server to local compact sql server data. I write two method one method check if any update date in remote server method like..[code]Last i Call SaveLocalDatabase method. But When i check table in my local compact sql server database there has no data update.is any think missing to write. i Think i found a problem. i use LocalTable.Merge(dTable, True). When Merge Call then rowstate remain unchange.
I am trying to merge multiple datacolumns in a datatable. Eg. The address data is stored in a different columns such as, Housename, street, city and postcode. I want to merge those datacolumns in to one and put it into one datacolumn as "Address".
Is there a way of merging (importing or whatver is the correct terminology is) the data from an Array in to a DataTable woithout looping. I already know how to loop through the array to populate the DataTable with new DataRow but I'm looking for something much faster if it exists. I've got a 1 dimensional String array i.e. 'String()' that I need to populate a DataTable with new DataRows.
I need to write a method in C# to save all rows in a given datatable back to the database, but I cannot depend on the rowstate of each row. I can't think of how best to do this without extensive looping through the database table data or constant database querying.
I want to essentially perform the following insert / update for each row in the datatable, but more efficiently:
I'm trying to understand why my print preview is not showing the contents of the file (I've double checked that the file is in the correct directory and is not empty)
Imports System.IO Imports System.Drawing.Printing Public Class Form1
my application will remain open after closing every form. This is a recent issue in previous versions my application would close. I call dispose(true) on all form closing/closed events. (some forms require it on closing instead of close because of some custom made classes.)?
I'm having an issue with a DataGridView object. This read-only grid is bound to a table and when a selection on the grid is made, other fields on the form get filled in with that row's data so the user can edit the row. When the user clicks another row, the current row's changes are saved back to the Table, making the row's RowState as modified.
The issue I'm having is an undo button I made. It just calls RejectChanges() on the row the user has selected. If I check the RowState after the button's click event function ends, the RowState is "Unchanged". However, if I click on another row, I notice that the RowState of the row I called RejectChanges() on gets changed back to Modified before the grid's SelectionChanged event is called, which is where I have the block of code that would store changes made to a row. If I go and check the data of that row, none of it has changed, so I'm quite confused as to what's making the row's RowState become Modified.
In RowCreated of the GridView i add following script to select a row:
Select Case e.Row.RowType Case DataControlRowType.DataRow e.Row.Attributes("onclick") = Me.Page.ClientScript.GetPostBackClientHyperlink(Me.MainGrid, "Select$" & e.Row.RowIndex) End Select
This works like a charm(i thought).But when i debug the SelectedIndexChanging and the following SelectedIndexChanged events, i observe that the RowState of the selected Row switches from normal{0}/alternate{1} to 3 instead of selected{2}. This occurs between SelectedIndexChanging and SelectedIndexChanged. Why does this happen? The next time i programmatically set the selectedIndex(f.e. after a new row was created), i have two rows that are selected and no (un-hacky) way to deselect the old in RowDataBound, because of the invalid RowState of 3(should only be 0,1,2,4 or 8).
I have a form with textboxes for input. I have coded the Exit button to display a message box that asks the user if they want to save any data in the textboxes before exiting the program:
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e
[code]....
The question I have if the textboxes are blank (nothing has been entered), how do I code the Exit button to close the program without displaying the message box asking the user to save the data.' Save the numbers. Call the btnSave_Click procedure.
I add a row to the DataSet using the following code: Dim NewRow as DataRow NewRow = gds.Tables("TitleDataSet").NewRow NewRow("Title") = txtTitle.Text NewRow("Local_number") = nubLocalnumber.Value NewRow("Number_suffix") = txtNumberSuffix.Text etc.
This code executes without errors but the bound DataGridView remains unchanged (without including the new row). Obviously I am doing something wrong or I am omitting a vital command. What do I need to do in order to make the new row appear in the DataGridView? I did not choose to bind the DataGridView directly to the database table because the database is selected by the user at execution time. Instead I bound the DataGridView to the DataSet. I included the command:L dgvTitle.AllowUserToAddrows = True but that did not have any effect.
Solved. Was missing the final command:L gds.Tables("TitleDataSet").Rows.Add(NewRow)
How can I assign a value to a message box for when the default value displayed in the text box is unchanged. ie. If my default value is 17 and the user clicks ok without retyping a number, the Input value displayed in a textbox will be 0.
Currently I have:
Public Class Form1 Dim MyValue As Double Private Sub But_EnterInput_Click(sender As System.Object, e As System.EventArgs) Handles But_EnterInput.Click MyValue = CDbl(InputBox("Input a value", "Data Input", "17", 200, 400))
[code]....
This works however if the user types 17, the textbox will read 0. not what i want.
i am using MS ACCESS DATABASE for data processing in vb.net, so i need to change the "connection string" while re-compile in another machines ,so i want to make connection string as stable(unchanged for all environment)
i have got a text file with contents in the formatuser:hashand in other text file i have cracked hashes in the formathashasswordBut not in order as the first file..i need to take hash from each line in the first text file and compare it with the second file and if it finds it the hash part in the first text file should be rewritten with the corresponding password from the second file.
