I am reading dates from a table in a database to display in a DataGridView column that is formatted as a date. The problem is that when the value is null in the database my program errors out because it cant convert the value to a date. How do you guys handle this? *Edit: If I set the value of my date variable to "Nothing" it displays as "1/1/0001" in my DataGridView, and I would like the cell to be empty for the null dates.
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I've got a DataGridView that has a column that will show dates/times this column needs to be sortable so I use this to tell the DGV that it is storing Date type objects (so that sorting works fine automatically):[code]Now the problem is that there will be some records shown in this DGV that do not have a value for this date column. How can I display this? If I dont set a value for that column or I set it to Nothing then the cell just shows the minimum date value (01/01/1601).Oh and this DGV is not using data binding if that makes any difference. Perhaps this might be a good time for me to investigate this data binding lark though if that will help with this issue? I'm sure I recall seeing something about being able to use one value but display another value when you use data binding thats all.
View 6 RepliesI have run into this problem a few times and have never come up with a good answer. I figure others must have dealt with this already.I have a datareader returned from the database and I want to use the values therein however values may or may not contain NULL. I would like to have a unction that takes in the value from the datareader and returns the value if it is not NULL and blank space if it is NULL.The problem I have is that the data-type of the variable I am testing is variable. It can be a String, and Integer or a DateTime. Can anyone suggest a simple way to test the value and then return the original value (as same data-type if possible) or something else if it is NULL
View 5 RepliesI read stuff from a SQL DB (database) using a data set. Some of the columns in the DB may contain NULL. I want to go through the table in the dataset and print, or use in some other way, the data. But when I try to use a certain data that corresponds to a NULL in the DB my program crashes.How can I detect - in the dataset - that it has no value and that I shouldn't try to use it?
Private Sub Get�rendenLista(ByVal e As System.EventArgs)
'----------------------------------------------------------------------
' This function fetches a list of �rende from the table �rende
'----------------------------------------------------------------------
Dim cno As New SqlConnection
[code]....
I have some MS SQL field with NULL value. when i am trying to use below in VB.NET code no result comming...
1- dim sqlq as string = "Select * from table where name3 = null and address3 = null"
2- dim sqlq as string = "Select * from table where name3 = '' and address3 = '' "
But if same query # 1 i run direct SQL Query browser it works well.
I am trying to implement a function for my SSRS report which will return a color value depending on the values of three dates.
[Code]...
I am using following code in rowdatabound fn.
Protected Sub gvwMileStone_RowDataBound(ByVal sender As System.Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs)
[code]...
ddlEProjectLevels is dropdownlist in edititemtemplate.Whwn i click edit in 1st row ddlEProjectLevels gets loaded with data from database.But in 2nd row dropdownlist does not contain values.Again in 3rd it gets loaded from db.Means in alternate rows,when i click edit dropdownlist(ddlEProjectLevels) doesnot load values.Can anybody help?
Having problems with null dates in a mysql table. Have eventually found out that I can store a 'null' date in mysql as "0000-00-00" and I can run the 'insert' command to add a record to the mysql table. When I check on mysql workbench I can see the row has been inserted correctly and the date shows as "0000-00-00".However...When I try to load the table into a datagridview, I get an error = mysql Conversion Exception was unhandled = "Unable to convert MySQL date/time value to System.DateTime".
View 4 RepliesI've got a subquery that returns the most recent value from a child table. In some cases the subquery returns nothing. The query below fails at runtime because the inferred type of MemberPrice is decimal and is not nullable. [code]...
View 4 RepliesWhat are NULL values? Sometimes when I try to assign a query to variable, I get error saying:
Type-Cast-Error. txtMiddleName.Text = Reader.GetString(2)
How can I put it that if the value of the Middle is nothing then txtMiddleName.Text = "". Working on VS 2010 (VB.net) EDIT 1: This is the error Message I get (Line 364 is the above mentioned code)
On a ASP.net form, I need to add a textbox to update a date field in MS SQL server via stored procedure. I want to verify user input cant figure out the correct syntax to do so (please see below)
If d.Text <> "" Then
cmd.Parameters.Add("@date", SqlDbType.DateTime)
cmd.Parameters("@date").Value = Date.Parse(d.Text)
[Code].....
I need to round and print a price like below, but this does not handle null values.How can I handle null values on one line of code? DBRSet is an SQLDataReader and the price is money
<%= Math.Round(DBRSet("price"))%>
I have about 200 .aspx pages of this so I could also use some tips on how to change these in an easy way? Can I do a search and replace with a reg-exp or something like that?
In a WinForms app (VS2008 / .Net Framework 3.5) I bind data from SQL Server to controls. If there's a null value e.g. an employee has no middle name (allowed by business rules), when I browse that record at runtime an exception is thrown. So I code: If Not (row("middle_name") Is DbNull.Value then txtMiddleName.DataBindings.Add(New Binding("Text", row, "middle_name)). Say someone adds a middle name to this record, because the control had no databindings the dataset.HasChanges property is false and update stored proc doesn't run. I guess I could handle this like this: If txtMiddleName.Databindings.Count = 0 AndAlso txtMiddleName.Text <> "" Then row("middle_name") = txtMiddleName.Text. I guess I would have to do something similar to handle a value changing from not null to null.
View 8 RepliesI am using KeyPressEventArgs to restrict several text boxes to numeric entries only. Rather than repeat the code, I thought I would make a "RestrictToNumeric" subroutine and call it from each "KeyPress" event. Like So:
Private Sub txt1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txt1.KeyPress
RestrictToNumeric()
End Sub
[code].....
The problem I am encountering is that the variable 'e' is used before it has been assigned a value, causing a null reference at runtime.
So I tried to add Dim e As System.Windows.Forms.KeyPressEventArgs As?to the RestrictToNumeric sub.I cannot figure out what I need to "Dim" it as...
I have an RDLC report that I am rendering directly to the Response Stream as PDF (rather than using the ReportViewer). In the code that renders the report, it's DataSource is bound to a List(Of ClassA) objects defined in a custom assembly. This seems to work for the most part. My problem is that I can't seem to handle the situation where a nested object is null. For example, given ClassA and ClassB (the nested object) defined as follows:
Public Class ClassA
Public Id As Integer
Public Name As String
[Code]....
the report displays "#Error" if TheNestedObject is null. If TheNestedObject is not null, it correctly displays the Name.
Thought I'd see if Stack overflow is quicker than me testing something while I get a thousand interruptions from other work :)
I'm updating an old VB net application and trying to refactor some of the logic as I go. The app looks for data from a single date across a few tables and writes that view to a file.
Writing the query in SQL I'd get the equivalent of
SELECT * FROM table
WHERE CAST(FLOOR(CAST(table.date AS float))AS datetime) = '15-Jul-2010'
Ideally I'd use
SELECT * FROM table WHERE date=@input
and add a date object as a parameter to a System.Data.SqlClient.SqlCommand instance
Are those two comparable? Will I get the results I expect?
My textbox6 represents the dateprinted of my asssessment form.. i code it like this :
TextBox6.Text = My.Computer.Clock.LocalTime.Date
then in the my SAVE Button coded like this :
Dim cn As OleDbConnection
[code].....
Ive created one database Sql Server Compact Edition 2005, with one table ("Cliente") I know that I can created my database good, but i have a problem saving information since three textbox, in my table(With columns "Nombre" "Apellido" "Cliente". In my form there is a button save ("Guardar"). When I do click in my button appear the next message : "The column cannot contain null values. [ Column name = Nombre,Table name = Cliente ] " and happen the same with apellido and Id_Cliente. And this happen becouse my code cant save the information....
This is the code
Option Explicit On
Option Strict On
Imports System
Imports System.IO
Imports System.Data
[CODE]...
And the code for my button is:
Private Sub cmdguardar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdguardar.Click
Dim myconnection As SqlCeConnection
Dim mycommand As SqlCeCommand
[CODE]...
I'm using a database to store a load of data and some of which is the date from a datetimepicker and its storing the date and time for me. but its not saving the date and time for me its just leaving it blank any ideas
i set up the database vis the database creater in VB 08
call the field Dateout and the other column "Datetime" and i would of thought that would of saved me date and time.
in datetimepicker_value changed section ive got it down as datetimepicker.text as now.date.tostring
I used a code to get the dates between 2 dates from the database (column with dates dd/mm/yy) , I think it works nice first time,[code]as you see , the code let the user to insert a number and minus it form the date of today , then calculates the date that I want , after that I use BETWEEN Clause to get all dates between them But now , this code gets some data and overpasses others , I mean some of the dates is between the tow dates but the code never get it , why that happens ?
View 2 Repliesmy problem is want to use WHERE clause to extract only year that fulfill a specified criterion. My coding as below, the coding below is extract all the month,day and year. But i only want year only. I am using MS Access. My textbox(cbYear) can select January To December. Can anyone give me a guideline to correct the coding.
sql = "SELECT * FROM sumPercent WHERE plants = '" & yieldsummary.cbPlant.Text & "' AND [b]dates = #" & cbYear.Text & " #[/b] AND line = '" & ds.Tables("sumPercent").Rows(a).Item("line") & "'"
I have an accounts program. My cash book shows data based on date picked from DateTimePicker. Cash book is not entered everyday. I want to make my datetimepicker so that based on dates found in the database, it changes colour or enable / disable some dates, for which cash book has been entered. How is it possible?
View 6 Repliesi was wondering is there a build in class in vb.net for get a range of dates from a column:What i mean is say i had the following dates in a column
10/03/2012
11/01/2011
14/05/2011
[code].....
I am currently making a college project for which i need to send scheduled emails.I googled for it and found out the we can do it through outlook. Is there any way to automate that process through vb, so that it will check for the dates in the database and send an email whenever necessary?Outlook is not important for me... I just need to send scheduled emails.And i even need to send sms (single and bulk) according to the needs... is there any free API for that too???I have already tried the google sms feature but it didnt work for me
View 8 RepliesI have a field in my database that holds dates as strings in this format: dd/MM/yyyy Now I want to load then into a var as dates vb.net Dim dte as date I am having problems with the format. Vb doesn't recognize my date format as a date when I use this for expample:
vb.net
Dim strDate as string = "22/05/2010"
Dim dte as date
dte = CDate(strDate)
I'm working with time and attendance application and i need to do something will help the data entry that will use my application so i want to create form to insert enter/leave time and date for all employees
[Code]...
I'm working with time and attendance application and i need to do some thing will help the data entry that will use my application so i want to create form to insert enter/leave time and date for all employees
textbox1 for inserting start of employee code
textbox2 for inserting end of employee code
textbox3 for inserting the date and time for enter
textbox4 for inserting the date and time for leave
I have a database (MDB, Access) and I connect it to my program using an OLE object,
now I have in the db a column filled with dates (ddmmyy),
I want to search and view (in Data grid view) all the fields that has a date before a Specific Date that I define .
the code of search that I used is :
SQLstr = "SELECT * FROM tb WHERE anomber = '" & TextBox1.Text & "'"
I am currently using VB. I want to do a Calendar Control which have dates highlighted/selected. All these dates are retrieved from a database.
how to put all the dates into an array Second thing I need to know is how to highlight all the dates in the array.
I have done some research on the internet and they said something about selectedDates and selectedDates collection and dayrender. But frankly speaking, I can't really find any VB codes regarding this. Dates format will be in dd/MM/yyyy
Imports System.Data.SqlClient
Partial Class _Default
Inherits System.Web.UI.Page
[Code]....
I'm using one Access Database and DataSet, BindingSource And Table Adapter. My question is: how to fill one listbox on my form with dates from one row from Database.
Look at the picture:
[url]
So listbox needs to have 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20.
How to to this, code?
