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I have a sample code that I want to use to read the content of an Excel file in a DataGridView in a Winform application in Visual Studio 2022 with C# language, but the content of the Excel file is not displayed in the DataGridView. I use Windows 11.

To test the content of the Excel file, I can easily read it with a console application and display it in the program, but I cannot do the same in the DataGridView. I remember that a few months ago I had read data from an Excel file with the same code and used it in a program, but now I can’t and I don’t know where the problem is.

I updated Visual Studio 2022 to the latest version. Could the problem be related to the update?

    using System;
    using System.Data;
    using System.Data.OleDb;
    using System.Windows.Forms;
    
    namespace WindowsFormsApp1
    {
        public partial class Form1 : Form
        {
    // Declare the connection and the adapter objects
    private OleDbConnection conn;
    private OleDbDataAdapter adapter;

    // Declare the DataSet object to hold the data from the Excel file
    private DataSet ds;

    // Declare the path and the name of the Excel file
    private string path = @"C:\Users\Hamed\Desktop\ConsoleApp1\sample.xlsx";
    private string fileName = "sample.xlsx";

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        // Create the connection string based on the file extension
        string connectionString = "";
        string fileExtension = System.IO.Path.GetExtension(fileName);
        if (fileExtension == ".xls")
            connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties="Excel 8.0;HDR=Yes;IMEX=2"";
        else if (fileExtension == ".xlsx")
            connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties="Excel 12.0;HDR=Yes;IMEX=2"";

        // Create the connection and the adapter objects
        conn = new OleDbConnection(connectionString);
        adapter = new OleDbDataAdapter("SELECT * FROM [Sheet1$A1:C10]", conn);

        // Create the DataSet object and fill it with the data from the Excel file
        ds = new DataSet();
        adapter.Fill(ds);

        // Bind the data to the DataGridView
        dataGridView1.AutoGenerateColumns = true;
        dataGridView1.DataSource = ds.Tables[0];
    }

    private void button1_Click(object sender, EventArgs e)
    {
        // Create the command builder object to generate the update commands
        OleDbCommandBuilder cmdBuilder = new OleDbCommandBuilder(adapter);

        // Update the Excel file with the changes made in the DataGridView
        adapter.Update(ds.Tables[0]);

                // Show a message to confirm the update
                MessageBox.Show("The Excel file has been updated.");
            }
        }
    }

I made a DataGridView named dataGridView1 and then wrote this code. I have not made any other settings. I tested with .NET 8 and 7 as well as with .NET Framework 4.8, but it didn’t work. My problem is that the content is not displayed without any errors in DataGridView

2

Answers


  1. Chosen as BEST ANSWER

    The problem with my work was that I had forgotten to put the "Form1_Load" in the "Events > Load" section, and that's why the "Form1_Load" was not executed at all.


    Note: Make sure that the official Microsoft package for OleDB is installed for you. To install it, you can go to Nugget Package Manager and install it.


  2. I used your code and it works normally in Winforms (.net)

    But when I create a Winforms (.net framework), the following error will be reported:

    enter image description here

    If this is the case for you, you need to select Windows Forms App instead of Windows Forms App (.net framework) when creating Winforms.

    enter image description here

    If the above answer is not what you want, what error does your code report when it cannot read excel, or is it simply unable to read it?

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