How to import excel file to grid view in asp.net using c# AND save grid view to database sql server 2005

You can get data from Excel like database using System.Data.OleDb;

using System.Data.OleDb;

public DataSet ImportFromExcel(string file)
{
    // Create new dataset
    DataSet ds = new DataSet();

    // -- Start of Constructing OLEDB connection string to Excel file
    Dictionary<string, string> props = new Dictionary<string, string>();

    // For Excel 2007/2010
    if (file.EndsWith(".xlsx"))
    {
        props["Provider"] = "Microsoft.ACE.OLEDB.12.0;";
        props["Extended Properties"] = "Excel 12.0 XML";
    }
    // For Excel 2003 and older
    else if (file.EndsWith(".xls"))
    {
        props["Provider"] = "Microsoft.Jet.OLEDB.4.0";
        props["Extended Properties"] = "Excel 8.0";
    }
    else
        return null;

    props["Data Source"] = file;

    StringBuilder sb = new StringBuilder();

    foreach (KeyValuePair<string, string> prop in props)
    {
        sb.Append(prop.Key);
        sb.Append('=');
        sb.Append(prop.Value);
        sb.Append(';');
    }

    string connectionString = sb.ToString();
    // -- End of Constructing OLEDB connection string to Excel file

    // Connecting to Excel File
    using (OleDbConnection conn = new OleDbConnection(connectionString))
    {
        conn.Open();
        OleDbCommand cmd = new OleDbCommand();
        cmd.Connection = conn;

        // Get all Sheets in Excel File
        DataTable dtSheet = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);

        // Loop through all Sheets to get data
        foreach (DataRow dr in dtSheet.Rows)
        {
            string sheetName = dr["TABLE_NAME"].ToString();

            // Get all rows from the Sheet
            cmd.CommandText = "SELECT * FROM [" + sheetName + "]";

            DataTable dt = new DataTable();
            dt.TableName = sheetName.Replace("$", string.Empty);

            OleDbDataAdapter da = new OleDbDataAdapter(cmd);
            da.Fill(dt);

            // Add table into DataSet
            ds.Tables.Add(dt);
        }

        cmd = null;
        conn.Close();
    }

    return ds;
}

Then, you can dump the data into GridView like this:

void LoadDataIntoGridView()
{
    string file = "C:\\MyExcel.xlsx";
    System.Data.DataSet ds = ImportFromExcel(file);
    foreach (System.Data.DataTable dt in ds.Tables)
    {
        GridView gv = new GridView();
        gv.DataSource = dt;
        gv.AutoGenerateColumns = true;
        gv.DataBind();
        Panel1.Controls.Add(gv);
    }
}

About inserting data into SQL database. You need to learn SQL database.
You will not be able to work properly with SQL database without knowing the basic of it:
- How to connect to a SQL database
- How to CREATE DATABASE and CREATE TABLE
- How to perform the basic operations of SELECT, INSERT, UPDATE, DELETE

Example of CREATE TABLE:

CREATE TABLE `department`(
   id int IDENTITY(1,1) NOT NULL PRIMARY KEY,
   name varchar(50) NOT NULL,
   dateformation datetime NULL
)

Example of INSERT:

INSERT INTO department(id,name,dateformation)VALUES(1,'Sales','2012-10-27 09:00');

Tutorials of SQL database can be easily found every where.