Access :: C# - How To Check Image Field Is Null Or Not
Mar 28, 2011
Actually i have a table with 7 columns
1) Title varchar(100)
2)Description varchar(300)
3)ProfilePicture varbinary(max)
4) Image1 varbinary (max)
5)Image2 varbinary(max)
6)Image3 varbinary(max)
7)Image4 varbinary(max)
Image1,2,3,4 are not a mandatory fields so, when i inserted, i check it if it is not there then i insert null value, Now problem is when i retrive them if there is a row contain image1,2 are image content and 3,4 are null values dataset also filling as it is in database but when i checking like
[code]....
it shows error like
Unable to cast object of type 'System.DBNull' to type 'System.Byte[]'.
View 3 Replies
Similar Messages:
Jan 6, 2010
In Microsoft Access Database Form, I have a series of five fields. I would like to set up a field that is equal to the first field unless that field is null or 0. Then I want the field to be equal to the second field unless that field is null or 0, continuing the same way through the five fields. Being a newb, I have no idea how.
View 1 Replies
Mar 18, 2011
For MS Access, how to check if the particular field data exist?
View 4 Replies
Aug 20, 2010
I'm having trouble accomplishing the above. Below is all the mark up and code. I'm not getting error messages, but the validate image function is not working (fileupload portion is working ok).
In my attempt below---not sure if it's the simplest or best validation approach anyway---the "UserId" parameter appears during rendering to be empty---but in most methods I have it successfully containing or referring to the logged-in user's identification.
Following is the control that refers to the image field (page = advertisement.aspx):
<asp:Image ID="Image" runat="server" ImageUrl ='<%#Eval("UserId","Image.aspx?UserId={0}") %>'
Following is the successful code behind for the page image.aspx referred to above (page = image.aspx.vb):
[code]....
View 13 Replies
Nov 6, 2010
i am using the following in a stored procedure.
[code]....
[Code]....Handling NULL...Field not updating when NULL?
View 3 Replies
Jul 15, 2010
I have a detailsview with an update button one of the update fields is a checkbox which when is checked I want to automatically update a date field of when the checkbox was checked, am I going the right way with this code....... as I am getting a number of errors
Dim i As Integer
For i = 0 To detailsview2.Rows.Count - 1 Step i + 1
Dim row As GridViewRow = GridView1.Rows(i) [code]....
View 4 Replies
Apr 1, 2011
I have a DetailsView on the page and I have made one of the fields a TemplateField. In the EditItemTemplate and InsertItemTemplate I have a DropdownList that is databound to a table in my Sql Server database. I wanted to add an initial value to the DropdownList
namely "- select -" .
I set the AppendDataBoundItems property to true and added the initial value as a ListItem.Markup of the DropdownList
<asp:DropDownList ID="DropDownList_HP" runat="server"
AppendDataBoundItems="True" DataSourceID="SqlDataSource_HP" [code]...
This works fine for new input. The problem is however that the database already has records that were entered through a Windows Application and many of these records has a null value in this field and exceptions are thrown when I tried to open these records
and the system tried to set the SelectedValue of the DropdownList.After some more searching I found this help
http://msdn.microsoft.com/en-us/library/ms366709.aspx
So I changed the ListItem in the DropDownList markup to the following:
<asp:DropDownList ID="DropDownList_RefHospDV4" runat="server"
AppendDataBoundItems="True" DataSourceID="SqlDataSource_RefHosp" [code]...
This now solved the problem of opening a record where the value is null in the database, BUT now the RequiredFieldValidator is not validating anymore to make sure that a databound item is selected for this field and not the initial value "- select -". So basically now it is not checking anymore to see if valid input has been entered for the DropDownList and it accepts "- select -" thus it acts as if the field is not a required field anymore.
In short what is required is that I want to make sure that the user enters a valid selection in the DropDownList, but it must also cater for old records that do not have this field entered yet so that those old records can be opened in the DetailsView .Opening Old records (with null in that field):When these old records are opened in the DetailsView the DropDownlist should show "- select -" when the value in the database is null.
Saving records (old or new records):When saving the record in Insert mode or Update mode the RequiredFieldValidator should show that a valid input is not selected if the DropDownList is still on "- select -".
View 1 Replies
Jan 21, 2010
here is my code for selectiong some records from db table
string strSql = "select * from mtblNBD where SentTo=@SentTo and InternalStatus Is NULL order by DeadLine desc";
SqlCommand com = new SqlCommand(strSql, con);
com.Parameters.Add("@SentTo", SqlDbType.NVarChar, 50).Value = (string)Session["uname"];
here I am using parameters for SenTo field but not for NULL so it is ok... or should I use parameters for this field where value is NULL , if yes then how can I use parameter for this
View 8 Replies
Nov 12, 2010
I have a SQL database. I am getting a datatable from SQL. In SQL Query the table is having null values in the output. But when it is coming to the front end, the null values are replaced by empty values.
So in the front end in the datatable i am having empty values in some cells. I am trying to insert this datatable into access. For this i am using following code...
OleAdpData.InsertCommand.Connection = OleConn; // OleConn is the OleDbConnection
OleAdpData.InsertCommand.Connection.Open();
OleAdpData.Update(dtData); // dtData is the datatable
OleAdpData.InsertCommand.Connection.Close();
It is inserting the datatable to access database. But it is inserting the empty spaces as present in the datatable. I want to insert NULL into the cells in access datatable where the cells are empty. Where should i add my logic for this.
View 4 Replies
Aug 21, 2010
I want to Check Gr #(PK) of student wheter exist in table or not id exist show Msg in Label after lost focus from text box .. I tried AutoNumber in Access but it showing error while insertion
Note : im using form View control for insertion...
View 1 Replies
Oct 18, 2013
How to upload images with some conditions
Like
size not gretr than 50 kb
with = 110px, height 140 px
etc..
View 1 Replies
Mar 29, 2011
var pq = attributes.SingleOrDefault(a => a.AttributeName == PasswordQuestion").AttributeValue;
The above code will throw an error if null. What is the best way to handle this?The below code would work, but I can't help but feel there's a more graceful way?
var pq = (attributes.SingleOrDefault(a => a.AttributeName == "PasswordQuestion") != null) ? attributes.SingleOrDefault(a => a.AttributeName == "PasswordQuestion").AttributeValue : null;
View 1 Replies
Oct 21, 2010
I know for a fact that the SQL statement below returns NULL but my code statement "if (obj != null)" is not working.When I debug it I see a value of {} ... not sure what that is. Here is my code:
[Code]....
So, even if SQL returns NULL, it still validates obj as NOT NULL !
View 3 Replies
Feb 11, 2010
I have Sub that requires EventArgs as below.
Sub Testing(ByVal sender As Object, ByVal e As EventArgs)
If I want to call the Sub from PageLoad event, I wrote like this Testing(nothing,nothing)
Then, in the Sub, I would like to check If Argment is Nothing or not
Dim testID As String
If (CType(sender, LinkButton).CommandArgument) = Nothing
testID=Request.QuerySting("myID")
ELSE
testID=(CType(sender, LinkButton).CommandArgument).ToString
End If
I get Null error at if statement (If (CType(sender, LinkButton).CommandArgument) = Nothing)
View 1 Replies
Feb 10, 2011
I have an aspx page which allows a user to submit modified entries into the database, but when the user clicks Submit to fire the stored procedure I want to first run a check to see if a modified row with the same relationship exists.I am passing the results of the following query:
SELECT SwitchRoom.ModifiedID FROM SwitchRoom WHERE
SwitchRoomID = @ChkSwitchRmID", constring;
into a DataReader to determine if that relationship exists.I need it to determine whether the reader returns NULL to allow the procedure to execute, if it doesn't, then don't allow the user to save the information.I've tried the following:
if (dbreader = NULL)
{
Fire Procedure
}
else
{
"Error Message"
}
and I've even tried passing the reader into a datatable and running it against that without any luck.
View 5 Replies
Apr 4, 2011
How do you check for null with HtmlAgilityPack? I'm getting "Property or indexer 'HtmlAgilityPack.HtmlNode.HasChildNodes' cannot be assigned to -- it is read only" with the following.
if (Node.Element("TD").HasChildNodes = DBNull.Value)
I"m getting "Object reference not set to an instance of an object. " with
if (Node.Element("TD").HasChildNodes)
View 1 Replies
May 7, 2015
My query is that I have an sql field for image with db type "Image" , now I have successfully inserted some images in the form of bytes, now how to read those bytes of image from database and convert, show in gridview?
View 1 Replies
Feb 16, 2011
I have the following code
public class ProductDetails
{
private string _productid;
public string ProductID
{
get { return _productid; }
}
private string _description;
public string Description
{
get { return _description; }
}
private string _image;
public string Image
{
get { return _image; }
}
public ProductDetails(string productid, string description, string image)
{
_productid = productid;
_description = description;
_image = image;
}
}
public class DataAccess
{
private static string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
public ProductDetails GetProductDetails()
{
SqlConnection con = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand("ProductDetails", con);
cmd.CommandType = CommandType.StoredProcedure;
string productid = HttpContext.Current.Request.QueryString["productid"];
cmd.Parameters.Add(new SqlParameter("productid", SqlDbType.NVarChar)).Value = productid;
con.Open();
SqlDataReader reader = cmd.ExecuteReader();
reader.Read();
ProductDetails pro = new ProductDetails(
(string)reader["ProductID"], (string)reader["Description"], (string)reader["Image"]);
reader.Close();
return pro;
}
}
protected void PopulateControls()
private DataAccess da = new DataAccess();
{
ProductDetails product = da.GetProductDetails();
if (product.Description == String.Empty)
{
lblDescription.Visible = false;
}
else
{
lblDescription.Text = product.Description;
}
}
In the last piece i want to check if the Description field is null or empty in order to hide the label control but i get an error if i write: if (product.Description == DBNull.Value) and can only use ring.Empty. But i want to check for NULL values as well..
View 3 Replies
Apr 4, 2011
So I took over this project and one page is throwing a lot of errors. I would need to refactor the whole thing but as always time is an issue.
In one case the code check's whether a datareader has any rows and if not go to an error page. However as the code is now the datareader can be null (didn't successfully connect to db) and in those cases I can't use
if (!dr.HasRows)
//
becasuse it obviously gives me 'nullreferenceexception was unhandled by code'. I tried with !dr.Read but same thing.
A part of the code is something like
SqlDataReader dr = null;
try
{
//connect to db etc
dr = DbHelper.GetReader("sp_GetCustomer", param);
}
catch
{
//show an error message
}
// and then:
if (!dr.HasRows)
{
}
View 2 Replies
Aug 27, 2013
If i have a page in which I want to check whether session is null.
If it is null it will redirect to other page.
But i also have a if (!Page.IsPostBack)
so i will check the session inside this if (!Page.IsPostBack) or outside it?
View 1 Replies
Jun 9, 2010
I have a data type mismatch while inserting into a number field in an access database using a parameterized query.I think this should be pretty simple but I am still learning a lot.
[Code]....
I have some commented out as I am working one field at a time. The working fields are textboxes and the non working ones are dropdown lists. But I think it may be the field that the list is drawing from? Not sure.
View 2 Replies
Nov 29, 2012
I am developing an application in which i have to store image in database SQL server2008. I want to use upload file control and only want to upload .jpg and JPEG file and view this image in image control . And when i want to update this record i can update that image too..
View 1 Replies
Jan 26, 2011
How can i check if an output parameter is null before i bind it to a asp literal, and if it is null i want to just make the literal
hname1.Text = cmd.Parameters("@hotel1").Value
hname1.DataBind()
hname2.Text = cmd.Parameters("@hotel2").Value
[code]...
View 1 Replies
Aug 17, 2010
I have set the value of an int parameter to the attribute of a textbox.The textbox can be empty or null, how to check whether the parameter is empty or null?
View 5 Replies
Feb 4, 2011
Inside a function I need to check to see if a variable value is null, how to do this? I implemented the code but its not returning the value I thought it would return.If it's null I want to set the value of the variable, else I want to query the value from a table
[Code]....
View 5 Replies
