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  • Category: ASP.NET

    How to display record not found in vb.net

    How show error message when date is not avalable in sql otherwise it should pdf file can anyone help me how to do.
  • #767162
    messagebox class will not work in asp.net as it run on server. you need to use TRY .. CATCH to show and handle messages
    Put a label on form named 'errorLabel' and when you does not get any record then you can throw exception from program and show error message on label as below

    Try
    Dim Date = txtDate.Text
    Dim pdf As Byte()
    Dim ID As String
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As New SqlConnection(constr)
    Using cmd As New SqlCommand()
    cmd.CommandText = "SELECT Id, BinaryData FROM dbo.Reports WHERE date=@Date "
    cmd.Parameters.AddWithValue("@Date ", Date)
    cmd.Connection = con
    con.Open()
    Using sdr As SqlDataReader = cmd.ExecuteReader()
    if sdr.hasrows then
    sdr.Read()
    pdf = DirectCast(sdr("BinaryData"), Byte())
    ID = sdr("RunId").ToString()
    else
    //messagebox("records not found")
    Throw new Exception("records not found")
    end if
    End Using
    con.Close()
    End Using
    End Using

    Response.Clear()
    Response.ContentType = "application/pdf"
    Response.AppendHeader("Content-Disposition", Convert.ToString("attachment; filename=Report.pdf"))
    Response.BufferOutput = True

    'Response.AddHeader("Content-Length", Response.Length.ToString())
    Response.BinaryWrite(pdf)
    Response.[End]()
    Catch ex As Exception
    labelError.Text = ex.Message
    End Try

    Thanks
    Koolprasd2003
    Editor, DotNetSpider MVM
    Microsoft MVP 2014 [ASP.NET/IIS]

  • #767164
    Hi,

    messagebox will work in windows applications, in web applications you can handle it in no of ways using dialog box you can show the message what ever you want and using label you can show it but the thing is how you are customized that is more important.


    if(condition)
    {
    //record found case
    }
    else
    {
    string message = "Record not found..";
    System.Text.StringBuilder sb = new System.Text.StringBuilder();
    sb.Append("<script type = 'text/javascript'>");
    sb.Append("window.onload=function(){");
    sb.Append("alert('");
    sb.Append(message);
    sb.Append("')};");
    sb.Append("</script>");
    ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", sb.ToString());
    }


    Hope this will helpful to you...

    --------------------------------------------------------------------------------
    Give respect to your work, Instead of trying to impress your boss.

    N@veen
    Blog : http://naveens-dotnet.blogspot.in/

  • #767168
    Hi,
    Use Page.ClientScript.RegisterStartupScript as follows to call JavaScript Alert() function through code behind :

    if sdr.hasrows then
    sdr.Read()
    pdf = DirectCast(sdr("BinaryData"), Byte())
    ID = sdr("RunId").ToString()
    else
    Page.ClientScript.RegisterStartupScript(Me.GetType(), "Window", "alert('records not found');", True)
    end if


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