zxing barcode generator example c# Part 5: Manipulating Excel Objects in C#

Drawer QR in C# Part 5: Manipulating Excel Objects

20
QR Code 2d Barcode Maker In C#.NET
Using Barcode printer for .NET Control to generate, create QR Code 2d barcode image in VS .NET applications.
www.OnBarcode.com
Recognizing Quick Response Code In C#.NET
Using Barcode recognizer for .NET framework Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Part 5: Manipulating Excel Objects
Barcode Creation In C#
Using Barcode printer for Visual Studio .NET Control to generate, create barcode image in VS .NET applications.
www.OnBarcode.com
Bar Code Scanner In C#.NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Microsoft Office Excel 2003 Programming Inside Out Jumping to the last row is a bit more difficult because the concept of the last row is somewhat nebulous. After all, just because a worksheet can handle 65,536 rows of data doesn t mean that the user of that application wants to view rows that far down. Instead, it makes sense to look through the worksheet to find the last row with a value in the first column and treat that as the last row. To make the last row dynamic, a few changes need to be made to the program. First the LastRow constant needs to be switched to a variable like this:
Print QR In .NET
Using Barcode creator for ASP.NET Control to generate, create QR image in ASP.NET applications.
www.OnBarcode.com
Drawing QR Code ISO/IEC18004 In VS .NET
Using Barcode maker for VS .NET Control to generate, create QR Code 2d barcode image in VS .NET applications.
www.OnBarcode.com
Public LastRow As Long
QR Generator In VB.NET
Using Barcode creation for Visual Studio .NET Control to generate, create QR Code ISO/IEC18004 image in VS .NET applications.
www.OnBarcode.com
Matrix 2D Barcode Creator In C#.NET
Using Barcode encoder for Visual Studio .NET Control to generate, create Matrix 2D Barcode image in .NET applications.
www.OnBarcode.com
20
Drawing Bar Code In Visual C#
Using Barcode drawer for .NET Control to generate, create bar code image in .NET applications.
www.OnBarcode.com
PDF-417 2d Barcode Creation In Visual C#
Using Barcode creation for .NET Control to generate, create PDF417 image in .NET framework applications.
www.OnBarcode.com
Then the constant needs to be assigned an initial value when the user form is initially loaded. There are two ways to do this. The easiest way is just to assign it a valid row number such as 3 and then call GetData to load the initial values into the form. So, use the following code to create the UserForm_Initialize event.
QR Creator In C#.NET
Using Barcode encoder for .NET Control to generate, create QR-Code image in Visual Studio .NET applications.
www.OnBarcode.com
Make ISSN - 13 In C#.NET
Using Barcode encoder for .NET framework Control to generate, create ISSN image in VS .NET applications.
www.OnBarcode.com
Private Sub UserForm_Initialize() GetData End Sub
Bar Code Reader In Visual Studio .NET
Using Barcode Control SDK for ASP.NET Control to generate, create, read, scan barcode image in ASP.NET applications.
www.OnBarcode.com
ANSI/AIM Code 39 Creation In Visual Studio .NET
Using Barcode creator for .NET Control to generate, create Code 3/9 image in .NET applications.
www.OnBarcode.com
If users want to see the last line in the form, they will need to press the Last button. There are several ways to locate the last row in response to the user clicking the Last button. One way would be to scan through all of the data looking for the first empty cell in column one each time the Last button was clicked. A better way would be to scan through the worksheet and locate the first blank cell in column 1 and assign the value to LastRow, which is what the routine shown in the following listing does. This routine is located in the user form module.
Code 39 Extended Encoder In Java
Using Barcode creation for Android Control to generate, create Code 3 of 9 image in Android applications.
www.OnBarcode.com
Generating EAN 13 In Java
Using Barcode creation for Android Control to generate, create GS1 - 13 image in Android applications.
www.OnBarcode.com
Private Function FindLastRow() Dim r As Long r = 2
PDF417 Drawer In Visual Basic .NET
Using Barcode printer for .NET Control to generate, create PDF-417 2d barcode image in VS .NET applications.
www.OnBarcode.com
Generate UPC-A In Java
Using Barcode encoder for Java Control to generate, create UPC A image in Java applications.
www.OnBarcode.com
Do While r < 65536 And Len(Cells(r, 1).Text) > 0
Encoding Code 128A In Visual Basic .NET
Using Barcode maker for .NET Control to generate, create Code 128B image in .NET framework applications.
www.OnBarcode.com
Barcode Reader In C#.NET
Using Barcode Control SDK for .NET framework Control to generate, create, read, scan barcode image in VS .NET applications.
www.OnBarcode.com
r = r + 1 Loop FindLastRow = r End Function
The FindLastRow function scans through the worksheet to find the first cell that doesn t have a value. A simple While loop iterates through each cell in column one of the worksheet, and the length of the return value is tested to see if the length is zero. If the length is zero, the loop will end and r will point to the last row in the worksheet, which is the first blank row follow ing the data in the worksheet. 426
Part 5: Manipulating Excel Objects
Creating Advanced User Forms Then you can set the LastRow variable by adding the following line to the UserForm_Initialize event.
LastRow = FindLastRow
The FindLastRow function can also be used in the event associated with the Last button to update the LastRow variable as well as set the value for the RowNumber control.
Private Sub CommandButton4_Click() LastRow = FindLastRow - 1
RowNumber.Text = FormatNumber(LastRow, 0)
End Sub
Editing Data
At this point, you can view any row of data in the worksheet, but any changes you make in the data displayed on the form aren t saved in the worksheet. There are a lot of different techniques you can use, but here s one that should work well for you. In this approach, the data displayed on the form is kept separate from the cells on the worksheet until the user explicitly presses either the Save or the Cancel button. Pressing the Save button should copy the data from the form to the worksheet, whereas pressing Cancel should reload the data from the worksheet, overwriting any changes in the user form that may have been made by the user. Both the Save and Cancel buttons should be disabled until the data on the form is actually changed. The easiest way to disable these buttons is to set their Enabled property to False. Then change the Enabled property to True once one of the values in the field changes. You can reduce the amount of work by creating two subroutines, one named EnableSave and one named DisableSave, which enable and disable the command buttons associated with Save and Cancel, respectively. Then, in the Change event associated with the text boxes that contain data, add a call to the EnableSave subroutine. This setting means that any change to the data will mark the entire form as dirty, meaning that the data in the form is different from the data on the worksheet. Because loading the data directly from the source means that the data is clean, the Save and Cancel buttons should call the DisableSave routine. This call should be placed only after the data is loaded onto the form because it s possible that the user might not have entered a valid row number and GetData might not actually reload any data. The PutData routine found in the user form module (shown in the following listing) is sim ilar to the GetData routine in that all the validations used to ensure that the value in RowNumber is valid are included. The main difference between the two routines is that the GetData routine copies information from the worksheet, whereas the PutData routine copies data to the worksheet.
Copyright © OnBarcode.com . All rights reserved.