Prevent Empty Columns From Loading In A Datacolumn?
Aug 13, 2009Prevent an empty column in Excel to be loaded into a dataset column?
View 3 RepliesPrevent an empty column in Excel to be loaded into a dataset column?
View 3 Replieshow to prevent an empty column in Excel to be loaded into a dataset column?
View 10 RepliesI am trying to prevent the User from proceeding if a specific text box is empty. All of the following lines of code SEEM TO work:
If txtTitle.text = "" Then.....
If txtTitle.Text = Nothing Then.....
If txtTitle.text = Nothing Then.....
(followed by a message box advising of the need for input)
The problem is, if the User enters a space (either accidentally or intentionally) all three of the above recognize the space as a valid entry.
I have a VB.NET program. In proerties/Application I checked Make a Single Instance Application. But it still allows someone from opening the program while already opened. How can I prevent this?
View 3 Replieswhat is code i should use if i want to prevent user not to leave empty word in text box after user click save button.Oh ya, i am using visual studio 2005, databse sql 2005 .Here is my code
Private Sub btnregister_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnregister.Click
If MsgBox(" Are You Confirm", MsgBoxStyle.YesNo) = vbYes Then
[Code].....
what is code i should use if i want to prevent user not to leave empty word in text box after user click save button. i am using visual studio 2005, database sql 2005.
View 2 RepliesI am using VB.Net and VS 2008 to develop my web app. When I launch the app, pretty much all the pages get loaded (by that I mean the page_load event is triggered). This happens even for pages that I created. When this happens, the app throws some errors (if a particular value has not been loaded from the database) and thus results in javascript errors (yellow icon at the bottom of IE). How can I figure out "what" is causing the pages to load, and how can I prevent the pages from being loaded without code-prompting.
View 1 RepliesI have a form contains NumericUpDown1, TextBox1, TextBox2, at design time i set NumericUpDown1.Value to 4 and TextBox2.Text to 100, and i have this sub[code]...
View 13 RepliesI coded this program. It has three forms, when I try to open the [Design] on one of the forms it give me this error: To prevent possible data loss before loading the designer, the following errors must be resolved:
[Code]...
I have a datagrid with 5 columns.2 of these columns will have data entered into them automatically - depending on the entries of 2 textboxes.I can disable these 2 columns ok.How can I have it so that the tab key doea not enter the cells of these 2 disabled columns. ideally I'd like the tab to enter the cells of the abled columns only.
View 4 RepliesI've got a Program and a text file, this text file gets load into the list box but that's not the problem. The problem is that when I make the text file it makes a open line and this line gets loaded into the list box and I don't want empty items.
So here's code that I use to make text file
Public MySettingfile As String = My.Application.Info.DirectoryPath & "Process History.MemFreo" Dim myCoolWriter As New IO.StreamWriter(MySettingfile, True, System.Text.Encoding.Default)
myCoolWriter.WriteLine()
myCoolWriter.Close()
Assume a .NET class library code that, for example, writes to the Windows registry. Then this code has problem to run over internet, because default Internet policy does not give access to write to the registry.By adding a RequestMinimum statement in the assembly we can specify that the code requires permission to write to write to the registry. This will not alter the fact that the code does not have the permission, but will stop the assembly from loading; the runtime will throw a System.Security.Policy.PolicyException and identify the permission that is required.Do you now any other examples of using evidence, security policy and permissions (the key elements of code-access security) to prevent an assembly from loading on a web server?
View 1 RepliesHow can I open a tab delimited text file and remove the columns that are empty and the save it? Empty columns are those that have no value in the first row.
View 7 RepliesI need to read an xml document from a database record into an XDocument object in order for it to be deserialized. So that the deserialization will work, I need to apply a specific namespace to each of the level 1 elements. So XML looks a bit like this:
[Code]...
How do I prevent the blank/empty namespace being added to each child element of the element to which the required namespace has been applied?
I have a datagrid that will be accepting data from an external measuring device via the serial port. The grid is also open to editing records as well. Part of the process of making this grid user friendly is to intercept the "enter" key and move to the next cell until there is a value in the cell. This is only for some cells, other cells can be blank. I have worked out how to intercept the "enter" key from another post on this forum. Here is the code:
[Code]...
Is there a way to turn off all visual updates to a .NET form while I am manipulating it? When my program first loads, for example, I set the tab control to the tab that was last open. The user can see the program switching tabs.
I have looked into SuspendLayout and ResumeLayout, but either I don't understand what they are doing, or I am not using them correctly, because they don't seem to have any effect. Someone told me that there used to be a way to turn off paint events in VB 6. Does this still exist in .NET?
Is there a simple way to assign a populated datatable's columns to another empty datatable? That is, I want to copy a datatable's structure only but not its data.
View 6 RepliesI am creating a project in VB.NET in which one of the reports require that the name of employees should be displayed as column names and whatever work they have done for a stated period should appear in rows below that particular column.Now as it is clear, the columns will have to be added at runtime. Am using an ODBC Data source to populate the grid. Also since a loop will have to be done to find out the work done by employees individually, so the number of rows under one column might be less or more than the rows in the next column.Is there a way to create an empty data table and then update its contents based on columns and not add data based on addition of new rows.
View 1 RepliesI have a DataTable that I am creating and binding to a GridView. Currently the headers do not have any spaces and it makes it hard to read. I want to space them out but I'm having a minor issue.[code]I know that I can set the HeaderText in the columns declaration like below, but I won't know how any columns I am going to have. And would rather the columns be generated automatically. [code]
View 2 RepliesHow do I go about adding a ButtonColumn to a DataTable.
I am basically using a DataTable as the DataSource of a DataGrid and need to add a ButtonColumn to the DataTable so that when I DataBind it to the DataGrid it all works.
Although when I try
dt.Columns.Add(buttonColumn)
This is not allowed. It has to be a basic DataColumn.
Anyone have any ideas what would prevent my data from not be ing able to be bound to my data column? [code]My error says cant bind to column named SellingPrice? I have many other columns ALL binding the same way and other parts of my program recognize SellingPrice ?
View 9 RepliesIs there a way to change when an expression in a datacolumn is evaluated?
I'm trying to make a simple total function which sums the values of a particular column in a data grid. Normally the expression is evaluated when I leave from the datagridview, but I wish it to be evaluated when the row is changed.
in my datatable I've a String.Byte[] column which contains the array of bytes of an image. So, when the datatable is binded to the datagrid, I can see the picture, if present, and the red cross if is not presente. So I can remove the red cross, by assign a value to the DefaultValue property of the datacolumn. But what default value I've to assign?? I tried with system.dbnull.value but the red cross is still present.
View 8 RepliesFirst of all - It`s my first post here so welcome I have a short question.I have an array with strings values, and a datacolumn with values of the same data type. The question is - what is the most efficient method to find values which are in the array, but aren`t in the datacolumn?
View 18 RepliesThis is the code I have:
Sub Main()
Dim dts As New DataSet
Dim da As New SqlDataAdapter
Dim SolTabla As New DataTable
[code]....
For example, I want to access the second cell value in "Columna". How can I do this with no using a Datagrid?
I have a dataset with a number of data columns, due to sizing issues I've updated a number of the varchar columns from say VARCHAR(20) to VARCHAR(50).I'd like the DataTable to automatically grab the new column information, is this possible? I'd rather not go through each column in the table and update the length.
View 1 Repliesi read an article about datacolumn.expression property here [URL]. this is really great. but i was just wondering, for my case i want to use my custom function to use in the expression. basically, on my datatable i added an unbound column AGE. when i display records, i just want the age textbox to be populated with the computation of the person's age based on birthdate.
View 7 RepliesI defined a DateTime datacolumn in a datatable dt as [code]]....
View 5 RepliesI'm adding a DateTime DataColumn to a DataTable like this:
Dim colDate As DataColumn = New DataColumn("Date")
colDate.DataType = System.Type.GetType("System.DateTime")
dt.Columns.Add(colDate)
Then when I try to add it to my datatable, if the value is Nothing I get an error saying string was not recognized as a valid DateTime. I'm having trouble getting this to work.
Can anyone demonstrate with an example how to shift the position of a datacolumn in a specific position after it is added at the end of a datatable.For example lets say I have a datatable with 9 columns and 5 rows. Now I added a 10th column. However I need this new column as the 5th column which requires shifting. How do I perform this shifting?
View 3 Replies