Creating Windows Forms applications that can open Excel files on button click is a common requirement for desktop applications. Whether you’re building data entry forms, report generators, or file processing tools, integrating Excel operations with button click events is essential.
Common Scenarios
- 📁 Open Excel File Dialog: Let users select Excel files
- 📊 Process Excel Data: Read and display Excel content
- 💾 Export to Excel: Generate Excel files from form data
- 🔄 Update Excel Files: Modify existing Excel files
Setting Up Windows Forms Project
First, create a new Windows Forms project and add the Openize.OpenXML SDK:
<PackageReference Include="DocumentFormat.OpenXml" Version="3.2.0" />
using Openize.Cells;
using System;
using System.IO;
using System.Windows.Forms;
Example 1: Open Excel File on Button Click
public partial class ExcelForm : Form
{
private string selectedFilePath = "";
public ExcelForm()
{
InitializeComponent();
}
// Button click to open file dialog
private void btnOpenFile_Click(object sender, EventArgs e)
{
using (OpenFileDialog openFileDialog = new OpenFileDialog())
{
// Configure file dialog
openFileDialog.Filter = "Excel Files|*.xlsx;*.xls|All Files|*.*";
openFileDialog.Title = "Select Excel File";
openFileDialog.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Documents);
if (openFileDialog.ShowDialog() == DialogResult.OK)
{
selectedFilePath = openFileDialog.FileName;
lblFileName.Text = $"Selected: {Path.GetFileName(selectedFilePath)}";
btnProcessFile.Enabled = true;
// Immediately show file info
DisplayFileInfo();
}
}
}
private void DisplayFileInfo()
{
try
{
using (var workbook = new Workbook(selectedFilePath))
{
var worksheet = workbook.Worksheets[0];
lblWorksheetName.Text = $"Worksheet: {worksheet.Name}";
lblRowCount.Text = $"Rows: {worksheet.GetRowCount()}";
lblColumnCount.Text = $"Columns: {worksheet.GetColumnCount()}";
}
}
catch (Exception ex)
{
MessageBox.Show($"Error reading file info: {ex.Message}", "Error");
}
}
}
Example 2: Process Excel Data and Display in DataGridView
public partial class ExcelProcessorForm : Form
{
// Button click to process Excel file
private void btnProcessExcel_Click(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(selectedFilePath))
{
MessageBox.Show("Please select an Excel file first.", "No File Selected");
return;
}
try
{
ProcessExcelFile(selectedFilePath);
MessageBox.Show("Excel file processed successfully!", "Success");
}
catch (Exception ex)
{
MessageBox.Show($"Error processing Excel file: {ex.Message}", "Error");
}
}
private void ProcessExcelFile(string filePath)
{
using (var workbook = new Workbook(filePath))
{
var worksheet = workbook.Worksheets[0];
// Clear existing data
dataGridView1.Rows.Clear();
dataGridView1.Columns.Clear();
int rowCount = worksheet.GetRowCount();
int colCount = worksheet.GetColumnCount();
// Add columns to DataGridView
for (int col = 1; col <= colCount; col++)
{
string headerText = worksheet.Cells[GetCellReference(1, col)].GetValue();
if (string.IsNullOrEmpty(headerText))
headerText = $"Column {col}";
dataGridView1.Columns.Add($"Col{col}", headerText);
}
// Add rows to DataGridView
for (int row = 2; row <= rowCount; row++)
{
string[] rowData = new string[colCount];
for (int col = 1; col <= colCount; col++)
{
string cellRef = GetCellReference(row, col);
rowData[col - 1] = worksheet.Cells[cellRef].GetValue();
}
dataGridView1.Rows.Add(rowData);
}
// Update status
lblStatus.Text = $"Loaded {rowCount - 1} rows and {colCount} columns";
}
}
static string GetCellReference(int row, int col)
{
return $"{GetColumnLetter(col)}{row}";
}
static string GetColumnLetter(int columnNumber)
{
string columnLetter = string.Empty;
while (columnNumber > 0)
{
columnNumber--;
columnLetter = (char)('A' + columnNumber % 26) + columnLetter;
columnNumber /= 26;
}
return columnLetter;
}
}
Example 3: Export Form Data to Excel on Button Click
public partial class DataExportForm : Form
{
// Button click to export data to Excel
private void btnExportToExcel_Click(object sender, EventArgs e)
{
try
{
using (SaveFileDialog saveFileDialog = new SaveFileDialog())
{
saveFileDialog.Filter = "Excel Files|*.xlsx";
saveFileDialog.Title = "Save Excel File";
saveFileDialog.FileName = "ExportedData.xlsx";
if (saveFileDialog.ShowDialog() == DialogResult.OK)
{
ExportDataToExcel(saveFileDialog.FileName);
MessageBox.Show($"Data exported successfully to:\n{saveFileDialog.FileName}", "Export Complete");
}
}
}
catch (Exception ex)
{
MessageBox.Show($"Error exporting data: {ex.Message}", "Export Error");
}
}
private void ExportDataToExcel(string filePath)
{
using (var workbook = new Workbook())
{
var worksheet = workbook.Worksheets[0];
worksheet.Name = "Exported Data";
// Export form data
worksheet.Cells["A1"].PutValue("Name");
worksheet.Cells["B1"].PutValue("Email");
worksheet.Cells["C1"].PutValue("Phone");
worksheet.Cells["D1"].PutValue("Department");
// Get data from form controls
worksheet.Cells["A2"].PutValue(txtName.Text);
worksheet.Cells["B2"].PutValue(txtEmail.Text);
worksheet.Cells["C2"].PutValue(txtPhone.Text);
worksheet.Cells["D2"].PutValue(cboDepartment.Text);
// Export DataGridView data if available
if (dataGridView1.Rows.Count > 0)
{
// Add headers from DataGridView
for (int col = 0; col < dataGridView1.Columns.Count; col++)
{
worksheet.Cells[GetCellReference(4, col + 1)].PutValue(dataGridView1.Columns[col].HeaderText);
}
// Add data rows
for (int row = 0; row < dataGridView1.Rows.Count; row++)
{
for (int col = 0; col < dataGridView1.Columns.Count; col++)
{
var cellValue = dataGridView1.Rows[row].Cells[col].Value?.ToString() ?? "";
worksheet.Cells[GetCellReference(row + 5, col + 1)].PutValue(cellValue);
}
}
}
workbook.Save(filePath);
}
}
}
Example 4: Complete Excel Manager Form
public partial class ExcelManagerForm : Form
{
private string currentFilePath = "";
public ExcelManagerForm()
{
InitializeComponent();
UpdateButtonStates();
}
// Open Excel file
private void btnOpen_Click(object sender, EventArgs e)
{
using (OpenFileDialog ofd = new OpenFileDialog())
{
ofd.Filter = "Excel Files|*.xlsx;*.xls";
if (ofd.ShowDialog() == DialogResult.OK)
{
currentFilePath = ofd.FileName;
LoadExcelFile();
UpdateButtonStates();
}
}
}
// Create new Excel file
private void btnNew_Click(object sender, EventArgs e)
{
try
{
using (var workbook = new Workbook())
{
var worksheet = workbook.Worksheets[0];
worksheet.Name = "New Sheet";
// Add some default content
worksheet.Cells["A1"].PutValue("Column 1");
worksheet.Cells["B1"].PutValue("Column 2");
worksheet.Cells["C1"].PutValue("Column 3");
using (SaveFileDialog sfd = new SaveFileDialog())
{
sfd.Filter = "Excel Files|*.xlsx";
if (sfd.ShowDialog() == DialogResult.OK)
{
workbook.Save(sfd.FileName);
currentFilePath = sfd.FileName;
LoadExcelFile();
UpdateButtonStates();
MessageBox.Show("New Excel file created!", "Success");
}
}
}
}
catch (Exception ex)
{
MessageBox.Show($"Error creating file: {ex.Message}", "Error");
}
}
// Save changes to Excel file
private void btnSave_Click(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(currentFilePath))
{
MessageBox.Show("No file is currently open.", "No File");
return;
}
try
{
SaveDataGridToExcel();
MessageBox.Show("File saved successfully!", "Saved");
}
catch (Exception ex)
{
MessageBox.Show($"Error saving file: {ex.Message}", "Save Error");
}
}
private void LoadExcelFile()
{
try
{
using (var workbook = new Workbook(currentFilePath))
{
var worksheet = workbook.Worksheets[0];
// Load data into DataGridView
dataGridView1.Rows.Clear();
dataGridView1.Columns.Clear();
int rowCount = worksheet.GetRowCount();
int colCount = worksheet.GetColumnCount();
// Add columns
for (int col = 1; col <= colCount; col++)
{
string header = worksheet.Cells[GetCellReference(1, col)].GetValue();
dataGridView1.Columns.Add($"Col{col}", string.IsNullOrEmpty(header) ? $"Column {col}" : header);
}
// Add rows
for (int row = 2; row <= rowCount; row++)
{
string[] rowData = new string[colCount];
for (int col = 1; col <= colCount; col++)
{
rowData[col - 1] = worksheet.Cells[GetCellReference(row, col)].GetValue();
}
dataGridView1.Rows.Add(rowData);
}
lblFileName.Text = Path.GetFileName(currentFilePath);
lblStatus.Text = $"Loaded: {rowCount - 1} rows, {colCount} columns";
}
}
catch (Exception ex)
{
MessageBox.Show($"Error loading file: {ex.Message}", "Load Error");
}
}
private void SaveDataGridToExcel()
{
using (var workbook = new Workbook(currentFilePath))
{
var worksheet = workbook.Worksheets[0];
// Save headers
for (int col = 0; col < dataGridView1.Columns.Count; col++)
{
worksheet.Cells[GetCellReference(1, col + 1)].PutValue(dataGridView1.Columns[col].HeaderText);
}
// Save data
for (int row = 0; row < dataGridView1.Rows.Count; row++)
{
for (int col = 0; col < dataGridView1.Columns.Count; col++)
{
var value = dataGridView1.Rows[row].Cells[col].Value?.ToString() ?? "";
worksheet.Cells[GetCellReference(row + 2, col + 1)].PutValue(value);
}
}
workbook.Save();
}
}
private void UpdateButtonStates()
{
bool hasFile = !string.IsNullOrEmpty(currentFilePath);
btnSave.Enabled = hasFile;
btnProcess.Enabled = hasFile;
}
}
Best Practices
- Always Use Try-Catch: Handle file operations safely
- Validate File Paths: Check if files exist before processing
- User Feedback: Show progress for long operations
- Enable/Disable Buttons: Update UI state based on context
- File Filters: Use appropriate filters in dialogs
Conclusion
Integrating Excel operations with Windows Forms button clicks provides powerful desktop functionality. The Openize.OpenXML SDK makes it easy to:
- ✅ Open Excel files through dialogs
- ✅ Process and display Excel data
- ✅ Export form data to Excel
- ✅ Create complete Excel management interfaces
Start building professional Excel-enabled Windows Forms applications today!