I am trying to retrieve the contents for one cell from my database table from codebehind, but It keeps returning NULL with this error
System.NullReferenceException: Object reference not set to an instance of an object.
It errors out at this line: dt = dv.ToTable();
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the syntax for retrieving a value from a SqlDataSource? I've managed to get it working using numbers to represent the column, but I'd much rather use it's DB name?
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I have a GridView, in which the width of each column is dynamic and changes depending on the dataset. I need to get the width of each column for use in my PDF exporter, but the column/cells width is always '0', presumably because I haven't set the width property.
Is there a way around this?
What is the problem:
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Not stored in the database.
how to find the data in a particular cell of a datatable using a reference value of another cell of same row
i've got two columns in a datatable andi want to retrieve a value from one of the row (say from column 2), with reference to the data present on Column 1.
How to add a button at first column of gridview and get cell value in another column?
For example, add a button named it as "Click me". Once user clicks will get third column cell's (ID) value.
No sense in showing a competely blank column. how to make a GridView column invisible if every cell in that column is empty?
View 3 RepliesIs there anything special you have to do to retrieve Filestream data using a SqlDataSource? I'm using VB and have this as my sqldatasource:
<asp:SqlDataSource ID="SqlDataSourceReadPD" runat="server" etc...
SelectCommand="SELECT [PDIPAttachment] FROM [PositionDescriptions] WHERE ([CP_IDString] = @CP_IDString)">
<SelectParameters>
<asp:Parameter Name="CP_IDString" Type="String" />
</SelectParameters>
</asp:SqlDataSource>
PDIPAttachment is a FILESTREAM column in my table called PositionDescriptions
and this is some of my VB cod:
Dim dv As DataView = DirectCast(SqlDataSourceReadPD.Select(DataSourceSelectArguments.Empty), DataView)
Dim dr As DataRowView
For Each dr In dv
Dim data as Byte() = System.Text.Encoding.ASCII.GetBytes(dr("PDIPAttachment").ToString())
Next
The Filestream data has a PDF file in it, but what I"m getting back in "data" are 13 bytes consisting of: "System.Byte[]".
My gridview has a dropdownlist when the user clicks "Edit". my question is: How to I retrieve the value of the cell that contains a dropdownlist (when the user clicks on "Select")?
I am able to retrieve the information from the cell that has a textbox (textbox is displayed ONLY when the user clicks on Edit). But when I try to retrieve information from any cells that has a dropdownlist (dropdownlist is displayed ONLY when the user clicks on Edit), it comes up blank.
In order to retrieve the cell I have used the following below:
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I have created a asp.net webpage for viewing daily downloaded newspaper, saved as a pdf file in a selected folder (~/NEWS/{0}) within the web root directory. Also i have a SQL datasource linked, where the news table has two columns viz: date and filename.
I want to create a tiled listview where the date text is visible on the hyperlink. on clicking the hyperlink, the file name is retreived for the corresponding date and the pdf file opens in a fresh page.
I have tried going to the item template in listview and replacing the label control with a hyperlink control, but then not able to successfully proceed ahead.
I've created a Column button in datagrid using this code
<Columns>
<asp:ButtonColumn Text="Resend" ButtonType="PushButton" CommandName="Resend"></asp:ButtonColumn> </Columns>
But I don't know where to access the event of this Button, also I would like to know how to retrive the row data of this button
After i retrieved a set of datatable from database, i need to edit the rows value before binding to the gridview. for example, a set of datatable is retrived from database.
eg: [userid], [userEmail] --> 1 , james@hotmail.com
i would like to change "james@hotmail.com" to "james" then bind it to gridview. Every rows of [userEmail] will be separated with the mail extension (@hotmail.com) ... how should i do..?
is it possible to retrieve by using connection.getschema() the description item from a sql server table column, just like it's possible to retrieve the column name, data type, is nullable, column default value, etc? if so, how?
View 3 RepliesCurrently, I am working on Gridview of ASP.net VS2010. In this application
1. I want to select complete column on a selection of 1 single cell in that column.
2. Gridview have 2 groups into it. Each group having same column name.
Like
Unloading | Loading
Amount| Item | Amount| Item
| | |
If I select Loading-> Amount column, it should select Unloading->Amount and Loading->Amount column as well.
I a function that used a mySQL Data Adapter and inserts a new row.
I want the function to return the value of the auto-incremented column of the updated row.
Public Function addRow(ByVal colA as String, ByVal colB as String) As Integer
Dim dbConnection As New MySqlConnection("server=xxx; user id=xxx; password=xxx; database=xxx; pooling=false;")
Dim dbDataAdapter As New MySqlDataAdapter("SELECT * FROM table", dbConnection)
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The "Return..." line doesn't work and don't know what the correct code would be.
i want row index & column header(index) of the selected cell of datagrdview, all colums are dynamic.
View 3 Repliesi need to upload excel to sql database
my problem is that i have not fixed header
this command will not work
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I developed the grid view in which i define 2 columns(Common Name, Common ID). I wanted that when i edit particular cell of grid; if i select any cell of column "Common Name" then it tells the name of particular column name and when i click on any cell of column "Column ID", it shows that column name.
View 1 Replieshow to get one cell value in the excel sheet (ex=D:92)
View 1 Repliesi am using gridview where it fetches datas from sqldatasource, i want to made some calculations wit some fields from tables and then need to show in gridview. How to fetch single column values from sqldatasource. I only know this code which are used after displayed in gridview
Gridview1.Row.Cells[0].text.toString()
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i need to set the column width of my gridview.
However the the column in the gridview is dynamic created which might more or less depend on system logic.
I have try to set the column width in row_created event, rowDataBound event, but it show me that no column is available by using gridview.columns.count.
I have an ASP.NET/C# web application that has a GridView control. In the last column of that GridView control I have a template field that contains a menu. In the OnMenuItemClick event I get a reference to which row the event was fired from, in order to determine what value the ID field contains for the current row. Currently I reference this cell by it's index "gvr.Cells[1].Text". However, this is highly volatile since any changes to the location of the ID column breaks the code. How can I instead gain the value in the cell that has a column name (or some other name-like property) of "SomeID" from a GridViewRow reference?
View 6 RepliesI have a datagrid, I want to merging cell. I want my datagrid look like this
Material Name
1
2
3
4
..
31
Material A
100
200
150
220
..
500
Material B
1200
4500
..
600
I want to merge the cell programmitically when ItemDataBound.
1,2,3,...,31 are material date request. If I request Material B with quantity 4500 from 2nd until 4th the cell will be merge.
I already read about Merge Cell in Gridview in this forum, but this solution is different with datagrid.
Formview with some Accordion block. In the block there are some complex structure, displayed with GridView. (but the GriewView is generated dynamically by input ) For the GridView has some rows, I converted it into a string and stored it in a "Column" (or said "field") of a record.
But when i doing search. I cannot bind the gridview to the "column". because string has to be converted manually into dataset to be accepted by gridview.
I just hope to do the coverting in the "Selected" event and databind the gridview with the data converted.
How could I retrieve the current record?
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