.NET Connectivity to Access Database using C sharp

Problem

You want to connect to a Microsoft Access database that has a database password.

Solution

Use the Jet OLEDB:Database Password attribute in the connection string to specify the password.

File: AccessPasswordForm.cs

// Namespaces, variables, and constants

using System;

using System.Configuration;

using System.Text;

using System.Data;

using System.Data.OleDb;

//  . . .

private void connectButton_Click(object sender, System.EventArgs e)

{

    StringBuilder result = new StringBuilder( );

    // Build the connections string incorporating the password.

    String connectionString =

        ConfigurationSettings.AppSettings["MsAccess_Secure_ConnectString"]+

        "Jet OLEDB:Database Password=" + passwordTextBox.Text + ";";

    result.Append("ConnectionString: " + Environment.NewLine +

        connectionString + Environment.NewLine + Environment.NewLine);

    OleDbConnection conn = new OleDbConnection(connectionString);

    try

    {

        conn.Open( );

}

.NET Connectivity to Excel Workbook using C sharp

Connecting to a Microsoft Excel Workbook

Problem

You want to access data stored in a Microsoft Excel workbook.

Solution

Use the OLE DB Jet provider to create, access, and modify data stored in an Excel workbook.

1)Create workbook and sheet

using System;

using System.Configuration;

using System.Data;

private OleDbDataAdapter da;

private DataTable dt;

//  . . .

private void ExcelForm_Load(object sender, System.EventArgs e)

{

    // Create the DataAdapter da

    da = new OleDbDataAdapter("SELECT * FROM [Sheet1$]",

        ConfigurationSettings.AppSettings["Excel_0115_ConnectString"]);

    // Create the insert command.

    String insertSql = "INSERT INTO [Sheet1$] " +

        "(CategoryID, CategoryName, Description) " +

        "VALUES (?, ?, ?)";

    da.InsertCommand =

        new OleDbCommand(insertSql, da.SelectCommand.Connection);

    da.InsertCommand.Parameters.Add("@CategoryID", OleDbType.Integer, 0,

        "CategoryID");

    da.InsertCommand.Parameters.Add("@CategoryName", OleDbType.Char, 15,

        "CategoryName");

    da.InsertCommand.Parameters.Add("@Description", OleDbType.VarChar, 100,

        "Description");

    // Create the update command.

    String updateSql = "UPDATE [Sheet1$] " +

        "SET CategoryName=?, Description=? " +

        "WHERE CategoryID=?";

    da.UpdateCommand =

        new OleDbCommand(updateSql, da.SelectCommand.Connection);

    da.UpdateCommand.Parameters.Add("@CategoryName", OleDbType.Char, 15,

        "CategoryName");

    da.UpdateCommand.Parameters.Add("@Description", OleDbType.VarChar, 100,

        "Description");

    da.UpdateCommand.Parameters.Add("@CategoryID", OleDbType.Integer, 0,

        "CategoryID");

    // Fill the table from the Excel spreadsheet.

    dt = new DataTable( );

    da.Fill(dt);

    // Define the primary key.

    dt.PrimaryKey = new DataColumn[] {dt.Columns[0]};

    // Records can only be inserted using this technique.

    dt.DefaultView.AllowDelete = false;

    dt.DefaultView.AllowEdit = true;

    dt.DefaultView.AllowNew = true;

    // Bind the default view of the table to the grid.

    dataGrid.DataSource = dt.DefaultView;

}

private void updateButton_Click(object sender, System.EventArgs e)

{

    da.Update(dt);

}