Visual Studio C#: How to check a value against Access table?

Question

Visual Studio C#: How to check a value against Access table?

VAer-4038 776

 private void btnConnect_Click(object sender, EventArgs e)
        {
            //I have an Access file, file path: C:\Users\QR\Documents\UserDatabase.accdb ; file password is: Pa$$word123;
            //The access file has a table called User, and the table has a field called UserID (Employee UserID is unique, it is work PC, employee userID is same as Environment.UserName)
            //If Environment.UserName is not in the table, then it is first time that the person uses this application, and it will loop to another Registration form.

        }

I will need to write code to check if Environment.UserName is not in the table , how do write it? In general, I have no idea how to connect Visual Studio to Access database.

Thanks.

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Answer 1

Hi VAer,

You can use System.Data.OleDb Namespace to read and write data from access database. And please refer to this sample:

        private void button1_Click(object sender, EventArgs e)  
        {  
            if (isInDataBase("aa"))  
            {  
                MessageBox.Show("yes");  
            }  
            else  
            {  
                MessageBox.Show("No");  
            }  
        }  

        public bool isInDataBase(string username)  
        {  
            string connString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\data.accdb;Jet OLEDB:Database Password=Pa$$word123;";  
            using (OleDbConnection connection = new OleDbConnection(connString))  
            {  
                OleDbCommand command = new OleDbCommand("SELECT username FROM [Table]", connection);  
                connection.Open();  
                OleDbDataReader reader = command.ExecuteReader();  

                while (reader.Read())  
                {  
                    if(reader[0].ToString() == username) return true;  
                }  
            }  
            return false;  
        }

Best Regards, Dylan

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VAer-4038 776 Reputation points

2020-12-31T11:31:12.06+00:00

"SELECT username FROM [Table]

if(reader[0].ToString() == username) return true;

Thank you very much. I am a little bit confused about TWO username here, do they refer to same thing? I used UserID in my question.

Let us say, I have an employee John Miller, his employee User ID is johnm.
Environment.UserName is computer username (whatever it is called, it is just the code used in program), when the application runs in his work computer, Environment.UserName will be johnm
I have an Access file, there is a table User, which has a field called UserID. So I will need to check if Environment.UserName(johnm) is in table User field UserID