This is my method to bind in code behind,I want to call it through web method
Private Sub BindData()
Dim objtable As New DataTable("projectinfoclass")
Dim Conn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("conString").ConnectionString)
Dim Cmd As SqlDataAdapter = New SqlDataAdapter("select * from ProjectInfoNew", Conn)
Cmd.Fill(objtable)
projectinfolist.Clear()
For Each dr As DataRow In objtable.Rows
projectinfolist.Add(New Projectinfoclass With {
.ProjectNumber = dr("ProjectNumber").ToString(),
.projectId = dr("Projectid").ToString(),
.Projectname = dr("ProjectName").ToString(),
.projectmodifiedDate = dr("ProjectmodifiedDate").ToString(),
.Recordupdateddate = dr("Recordupdateddate").ToString(),
.ProjectLocation = dr("ProjectLocation").ToString(),
.LocationServerName = dr("LocationServerName").ToString(), .ProjectModifiedBy = dr("ProjectModifiedBy").ToString(),
.DBServer = dr("DBServer").ToString(),
.DBName = dr("DBName").ToString(),
.Flag = Nothing})
Next
GridView1.DataSource = objtable
GridView1.DataBind()
End Sub
put your GridView in a usercontrol and follow the solutions here:
How do I get the HTML output of a UserControl in .NET (C#)?
1) Keep the data source and bind bits in the page code behind, move the rest into a web method. The web method can be called in the code behind and you use the result.
or
2) move code into web method as above but use as an object data source in the aspx and that removes all the code behind wiring up.
I hope that's what you're after.
Related
I am working on a website with VB.NET and ASP.NET. I currently have recurring DropDownLists for the user to provide input.
The design is recurring. These DropDownLists get their values from a database table, Everything with the Web interface is working except for writing these recurring values to the database - that is just to give you some background.
I have set the ID's of each DropDownList like so:
FrequencyList.ID = String.Concat("FreqList", DBReader(0))
That is in a loop while reading the DatabaseReader.
This is what I'm having issues with (please note I simplified the code down to make it easier to read:
Dim i As Integer
DBCommand = New SqlCommand()
DBCommand.Connection = DBConnection
DBCommand.CommandType = Data.CommandType.StoredProcedure
DBCommand.CommandText = "StoredProcedureName"
DBConnection.Open()
For i = 1 To AspectTableLength
Dim ParamFrequencyID As SqlParameter = DBCommand.Parameters.Add("#nFrequencyID", SqlDbType.Int)
ParamFrequencyID.Value = FindControl("FreqList" & Convert.ToString(i))
ParamFrequencyID.Direction = ParameterDirection.Input
Next
The FindControl("FreqList" & Convert.ToString(i)) variable is incorrect because it does not access the value - and adding .SelectedItem.Value does not work.
I got help from a developer.
Dim MyControls As ControlCollection = Panel.Controls
Dim Number As Integer 'this is the same as "DBReader(0)"
For Each MyControl As Control In MyControls
If MyControl.ID Is Nothing Then
Else
If MyControl.ID.StartsWith("Span") Then
Number = Replace(MyControl.ID, "Span", "")
Dim Freq As DropDownList = PanelMain.FindControl(“FreqList” & Number)
Dim ParamFrequencyID As SqlParameter = DBCommand.Parameters.Add("#nFrequencyID", SqlDbType.Int)
ParamFrequencyID.Value = Freq.SelectedIndex
ParamFrequencyID.Direction = ParameterDirection.Input
DBCommand.ExecuteNonQuery()
DBCommand.Parameters.Clear()
End If
End If
Next
DBConnection.Close()
When I consuming a webservice (asmx) the first time and return a DataTable to my aspx project, everything is ok. However, if I consume the webservice again on that same aspx the previous DataTable object is completely empty. Why is that?
This is my webservice method:
<WebMethod()> _
public Function QueryGeneralText() As DataTable
ds.Reset()
com.Parameters.Clear()
com.CommandText = queryString
com.CommandType = select booksID from Books"
com.Connection = con
conectarBD()
da = New SqlDataAdapter(com)
da.Fill(ds)
con.Close()
Return ds.Tables(0)
End Function
On the aspx.vb section:
Public Sub CreateDatatable()
Dim example1 As DataTable = ws.QueryGeneralText() ' RETURNS DATA
Dim example2 As DataTable = ws.QueryGeneralText() ' RETURNS DATA, BUT EXAMPLE ITS EMPTY
End Sub
It looks like you are using a global ds object - so you function is working on the same resultset.
First time you execute the function it works, nobody else has any results in ds, but next time you already have results there but now your reset drops the results.
If this is true, you might fix it by creating the ds inside the function instead if possible.
this may sound like a silly question but i am learning Visual Basic ASP.NET 4 and i have been asked to create a DropDownList which obtains information from a table using SQL. I cant seem to pull the selected item from the dropdownlist and show it on the screen using Request.Form.
I have tried this..
Dim selItem As String = Request.Form("DDList")
Response.Write(selItem)
but this does not show anything on screen. Please help as i am struggling with this.
I have added my dropdownlist as follows:
<asp:DropDownList ID="DDList" runat="server" Width="201px">
</asp:DropDownList>
<asp:DropDownList ID="DDList2" runat="server" Width="145px">
</asp:DropDownList>
My Class/Function
Public Class sqlFunc
Public Shared Function tableData() As DataSet
Dim oraConnect As New OracleConnection
oraConnect.ConnectionString = ConfigurationManager.ConnectionStrings("smart_dev").ConnectionString
Dim oraCommand As New OracleCommand
oraCommand.Connection = oraConnect
oraCommand.CommandType = Data.CommandType.Text
Dim lsSQL As String = ""
lsSQL = "SELECT code, description FROM ref_code WHERE domain = 'SPECIALTY'"
oraCommand.CommandText = lsSQL
Dim da As New OracleDataAdapter(oraCommand)
Dim ds As New DataSet
da.Fill(ds)
Return ds
End Function
What i am using on my .aspx.vb page;
Dim dsData1 As New DataSet
dsData1 = tableData()
DDList.DataSource = dsData1
DDList.DataValueField = "code"
DDList.DataTextField = "description"
DDList.DataBind()
DDList.Items.Insert(0, New ListItem(String.Empty, String.Empty))
DDList.SelectedIndex = 0
You don't need to get the selected value using Request.Form if you are using an asp:DropDown ASP.net control. All you have to do is:
Dim selItem As String = DDList.SelectedValue
Response.Write(selItem)
If you really want to use Request.Form, do it like this:
Dim selItem As String = Request.Form(DDList.ClientID)
Response.Write(selItem)
Also, make sure you have ViewState enabled and that you do not rebind the DropDown at PageLoad when there is a PostBack:
Sub Page_Load
If Not IsPostBack
' Bind your DropDown here
End If
End Sub
I have a dropdownlist which I constantly use.
I wrote a method to load this dropdown.
Though when I call the method only the Text part of the item is passed.
This is the method
Public Shared Function ddlLoadResumes() As DropDownList
Dim connString As String = ConfigurationManager.ConnectionStrings("LocalSqlServer").ConnectionString
Dim conn As SqlConnection = New SqlConnection(connString)
Dim ddSelectResumeList As New DropDownList
Dim dtResumes As New DataTable()
Dim comm As SqlCommand = New SqlCommand("usr_SelectResumeList", conn)
comm.CommandType = CommandType.StoredProcedure
comm.Parameters.Add("#UserName", SqlDbType.VarChar, 50).Value = Membership.GetUser().UserName
Try
Dim daResumes As New SqlDataAdapter(comm)
conn.Open()
daResumes.Fill(dtResumes)
ddSelectResumeList.DataSource = dtResumes
ddSelectResumeList.DataTextField = "ResumeName"
ddSelectResumeList.DataValueField = "Res_ID"
ddSelectResumeList.DataBind()
' Handle the error
Catch ex As Exception
Finally
conn.Close()
End Try
Return ddSelectResumeList
End Function
and this is how I call it
ddSelectResume.DataSource = MailClass.ddlLoadResumes.Items
ddSelectResume.DataBind()
Dim ltitem As ListItem
For Each ltitem In ddSelectResume.Items
Response.Write(ltitem.Value + "-----" + ltitem.Text)
Next returns only the text part
I need both DataTextField and DataValueField.
Thank you in advance
This seems like kind of an odd approach. One thing to resolve your issue would be to just set the ddSelectResume equal to the DropDownList object your Function is returning:
ddSelectResume = MailClass.ddlLoadResumes
Dim ltitem As ListItem
For Each ltitem In ddSelectResume.Items
Response.Write(ltitem.Value + "-----" + ltitem.Text)
Next
Though I think a better approach would be to just have "ddlLoadResumes return the DataTable (dtResumes), and set that as the datasoure of ddSelectResumes (you'd still have to set the DataTextField and DataValueField properties).
I'm having a problem populating a child gridview using a function I define. I keep getting the error "Object reference not set to an instance of an object". What am I doing wrong? Am I using the FindControl function incorrectly? It doesn't seem to find the child gridview.
Sub RecordsByZip()
Dim DBConn As New SqlConnection(Application("DBConn"))
Dim gv1 As GridView
gv1 = grdTotal
Dim gv2 As GridView
gv2 = DirectCast(gv1.FindControl("grdChild"), GridView)
Dim ZipCode = lbZip.SelectedItem
For Each ZipCode In lbZip.Items
If ZipCode.Selected = True Then
Dim cmdZip As SqlCommand = New SqlCommand("spPICAInsertTotals2", DBConn)
cmdZip.CommandType = CommandType.StoredProcedure
strZip = ZipCode.Text
strUser = Session("User")
Dim Zip As New SqlParameter("#Zip", SqlDbType.VarChar)
Zip.Value = strZip
cmdZip.Parameters.Add(Zip)
Dim UserID As New SqlParameter("#UserID", SqlDbType.Int)
UserID.Value = strUser
cmdZip.Parameters.Add(UserID)
DBConn.Open()
gv1.DataSource = cmdZip.ExecuteReader
gv1.DataBind()
gv1.Visible = True
DBConn.Close()
End If
Next
btnExport.Visible = True
lblmsg.Visible = False
' Dim DBConn = New SqlConnection(Application("DBConn"))
Dim cmdCounty As SqlCommand = New SqlCommand("spPICAInsertTotals", DBConn)
cmdCounty.CommandType = CommandType.StoredProcedure
'Dim gv As GridView = TryCast(e.Row.FindControl("grdChild"), GridView)
strUser = Session("User")
Dim UserID2 As New SqlParameter("#UserID", SqlDbType.Int)
UserID2.Value = strUser
cmdCounty.Parameters.Add(UserID2)
DBConn.Open()
gv2.DataSource = cmdCounty.ExecuteReader
gv2.DataBind()
gv2.Visible = True
DBConn.Close()
btnExport.Visible = True
lblmsg.Visible = False
lblInstructions.Visible = False
End Sub
First of all . . .
Just as a disclaimer, I normally use repeater controls instead of gridview controls.
But this may help you . . .
I can tell you that with repeater controls, if you want to find a nested repeater then you must look for them inside the item of the parent repeater to which they belong. Essentially, what you are trying to do with the code above, is find grdChild when there might actually be several grdChild (it is a nested gridview, after all). I'd be willing to bet this is where you're object reference error is occurring.
In other words, if you want to find the nested repeater with the ID nestedRepeater, and you know it is located in the first item of your main repeater (which in this case I've assigned to the myRepeater variable), you can do this:
Dim myItem as RepeaterItem = myRepeater.Items(0)
Dim Rep2 as Repeater = myItem.FindControl("nestedRepeater")
Using SqlDataAdapter and a DataSet (recommended)
Dim sa As New SqlDataAdapter(cmdCounty) 'Initialize the SqlDataAdapter and assign the SqlCommand object to it.
Dim ds As New DataSet() 'Initialize the DataSet (we will bind this to the gridview)
Try 'The Try/Catch statements help you to handle errors.
cmdCounty.Connection.Open() 'Open the connection to the database.
sa.Fill(ds) 'This statement uses the SqlDataAdapter to easily execute the SqlCommand (using the query specified in the SqlCommand object) and . . .
'. . .use that data to fill our dataset.
cmdCounty.Connection.Close() 'These statement close the connection and dispose of the SqlCommand object. Note: You may only need the dispose command.
cmdCounty.Dispose()
Catch ex As Exception
'Catch your error here.
cmdCounty.Connection.Close()
cmdCounty.Dispose()
End Try
gv2.DataSource = ds 'Set the datasource for your GridView control.
gv2.DataBind() 'Bind the data.
Using SqlDataReader and a DataTable
According to your comment, you're code is breaking when you assign the gridview to the cmd.ExecuteReader.
You will need to access your data using a method like this:
Dim rdr as SqlDataReader = cmdCounty.ExecuteReader() 'Declare the SqlDataReader and set it to handle your SqlCommand.
Dim dt as New DataTable 'Initialize a new DataTable. This is where we will place the information we read using the SqlDataReader.
'Make sure you add the columns...
dt.Columns.Add("firstColumnName") 'Create a column for each field you will be retrieving data from.
dt.Columns.Add("secondColumnName")
Dim r as DataRow 'Declare the variable r as a DataRow.
'You may want to insert the line "If rdr.HasRows Then" to check if any data was pulled before attempting to read it.
While rdr.Read() 'Loop through each row in the reader.
r = dt.NewRow() 'Set r to equal a new DataTable in the DataTable we created. Note: This does not actually add the row to the table.
r("firstColumnName") = rdr("firstColumnName") 'Set the values of each column in the current DataRow to equal their corresponding data read from SQL.
r("secondColumnName") = rdr("secondColumnName")
dt.Rows.Add(r) 'Add the DataRow r to the DataTable.
End While 'Loop back until there are no more rows.
gv2.DataSource = dt
gv2.DataBind()
Both of these examples assume you have already created your SqlCommand object and have assigned a working SQL query string and Connection object to it.