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error in user and password windows form and sql

error in user and password windows form and sql

hustino siat

4y974Learn iOS Programming

So i tried this video tutorial on youtube about payroll login. When i enter the right input it works but when i iinput wrong it have an error..

I copy the exact code like on the YT.

heres the error:

heres the class connection:

3 Replies

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Sachin Singh4y ago
just modify your query and it should work
string username=txtUserName.Text;
string psd=txtPassword.Text;
string sql=$"select * from [UserInfo] where userName='{username}' and password='{psd}'";

con.DataGet(sql);
but, i will recommend to use parameterized query, rather than string interpolation or concatination.
Amit Mohanty4y ago
Hey change your DataGet() method to a return type function.
Ex-
public DataTable DataGet(string SQL)
{
    DataTable dataTable = new DataTable();
    try
    {
        Conection();
        sda = new SqlDataAdapter(SQL, con);
        sda.Fill(dataTable);
    }
    catch(Exception ex)
    { }
    return dataTable;
}
In your buttion click event call the function like
DataTable dt = con.DataGet("your query");
Muhammad Imran Ansari4y ago
It seems you are passing any empty value ot not according to the table datatype.

Perform the following steps to mitigate your problem:

1. Check your SQL table with datatype.

2. Check your passing wrong input according to table datatype.

I woud recomend implement validation step before hit to SQLor write a storeprocedure and pass your input with command parameters.