how to call the stored procedure in csharp

I'll give you Google[^].

The perfect way is to do the things is the proper way. you need to segregate the things accordingly.
for that first make a class file which will have all your Data access related function. For example

//in DataAccess.cs
//this function will return your a data table when you pass your SQL Command to it.
public static DataTable GetTable(SqlCommand cmd)
{
    DataTable tbl = null;
    SqlConnection conn = null;
    try
    {
        conn = //your DB Connection;
        cmd.Connection = conn;
        tbl = new DataTable();
        SqlDataReader dr = cmd.ExecuteReader();
        tbl.Load(dr);
        dr.Close();
        dr.Dispose();
    }
    catch (Exception ex)
    {
        throw ex;
    }
    finally
    {
        if (conn != null)
        {
            conn.Close();
        }
    }
    return tbl;
}
//In YourClassFile.cs
//Make a function which will call your Stored Procedure for the operation you want to perform. its return type is DataRow.
public static DataRow SampleStoreProcCall(Int32 prama1,Int32 Param2, String Prama3)
        {
            DataRow row = null;
            DataTable tbl = null;
            SqlCommand cmd = new SqlCommand();
            cmd.CommandText = "Sb_SampleStoreProc";
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@prama1", prama1);
            cmd.Parameters.AddWithValue("@prama2", Param4);
            cmd.Parameters.AddWithValue("@prama3", Param3);

            tbl = DataAccess.GetTable(cmd); // Call this from your DataAccess.cs class file
            row = tbl.Rows[0];
            return row;
        }


//Call of SampleStoreProcCall function in your yourAspxPage.aspx.cs
DataRow row = YourClassFile.SampleStoreProcCall(Callprama1,CallParam2, CallPrama3);
txtbox1.txt = row["column1"].ToString();
txtbox2.txt = row["column2"].ToString();
txtbox3.txt = row["column3"].ToString();

Hope this will help.

visit here...
how to call stored procedure in asp.net c# code[^]

using (SqlConnection con = new SqlConnection(dbclass.Con)) { // open connection here
   using (SqlCommand cmd = new SqlCommand("sp_sample", con)) {  //spsample -sp name
     cmd.CommandType = CommandType.StoredProcedure;

     cmd.Parameters.Add("@FirstName", SqlDbType.VarChar).Value = txtFirstName.Text;
     cmd.Parameters.Add("@LastName", SqlDbType.VarChar).Value = txtLastName.Text;

     con.Open();
     cmd.ExecuteNonQuery();