ASP.NET interview questions: - Creating a Unique Code in ASP.NET.

In order to see it practically you just need to follow the following steps: -

Step1: - Create an ASP.NET Web Application for that just open Visual Studio >> go to >> File >> New >> Project >> Web >> Select ASP.NET Empty Web Application.

Step2: - Now simply just add a Web Form in to your Web Application for that just go to Solution Explorer >> Right click on the Project name >> ADD >> New Item >> Select Web Form.

Step3: - Assume that we have the table of Customer like below diagram.

Step4: - Design your Web Form like below diagram.

Also add a GridView Control to your WebForm.aspx page.

Step5: - This is the most important step for creating Unique Customer code.

Add the below code snippet in to your WebForm.aspx.cs file.

        protected void Page_Load(object sender, EventArgs e)
        
            if (!IsPostBack)
            
                AutoGenerateCode();
            }
        }
        public void AutoGenerateCode()
        
            string Unique Code = "";
            SqlConnection con = new SqlConnection(str);
            con.Open();
            SqlCommand com = new SqlCommand();
            com.CommandText = "select CustCode from Customer where 

             CustomerID in (select max(CustomerID) from Customer)";
            com.Connection = con;
            SqlDataReader objRead = com.ExecuteReader();
            if (objRead.Read())
            
                UniqueCode = objRead[0].ToString();
                string sd = UniqueCode.Remove(0, 1);
                int sd1 = Int32.Parse(sd) + 1;
                UniqueCode = sd1.ToString();
                if (UniqueCode.Length == 3)
                
                    UniqueCode = "C" + UniqueCode;
                }
                if (UniqueCode.Length == 2)
                 
                    UniqueCode = "C" + "0" + UniqueCode; 
                }
                if (UniqueCode.Length == 1)
                
                    UniqueCode = "C" + "0" + "0" + UniqueCode; 
                }
            }
            else 
            
                UniqueCode = "C001"; 
            }
            objRead.Close();
            con.Close();
            TextBox3.Text = UniqueCode;
            //The below line will not allow 
            //the user to modify the Unique Code.
            TextBox3.ReadOnly = true;
        }

Once you have done with all the above steps simply run the application and will see the result like below diagram.

In the above code snippet you can clearly see that the Unique Customer Code is been generated.

 See the following video on ASP.NET Authentication, Authorization, Principal and Identity objects as follows: -

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Regards,

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