CODEWITHSUNDEEP
c#sql-server
tryingtotryhard
tryingtotryhard

Reputation: 134

Can't seem to get a DataReader to work in C# / SQL Server

I have this code:

string strConnect = "Server=DESKTOP-2Q73COU\\SQLEXPRESS;Database=LoginApp;Trusted_Connection=True;";
SqlConnection conn = new SqlConnection(strConnect);
conn.Open();

MessageBox.Show("Connected to SSMS.");

string loadMainInfo = "SELECT * FROM Main_Information WHERE Username = " + Globals.username;

SqlCommand cmd = new SqlCommand(loadMainInfo, conn);

SqlDataReader dr = cmd.ExecuteReader();

if (dr.Read())
{
    lblStanding.Text = (dr["Standing"].ToString());
    lblName.Text = (dr["First Name"].ToString()) + " " + (dr["Last Name"].ToString());
    lblTotalHours.Text = (dr["Total_hours"].ToString());
    lblType.Text = (dr["Degree_type"].ToString());
    lblDegree.Text = (dr["Degree"].ToString());
    lblCurrentHours.Text = (dr["Current_hours"].ToString());
}

Specifically this line:

string loadMainInfo = "SELECT * FROM Main_Information WHERE Username = " + Globals.username;

If I replace the end of that line with:

Username = testuser"

The code will work fine and all labels below will be populated with the corresponding info from the tables where Username = testuser. However, if the user logs in with their username and the code is using the original line, I get this error:

System.Data.SqlClient.SqlException: 'Incorrect syntax near '='.'

Any help?

Upvotes: 0

Views: 81

Answers (4)

Saliou673
Saliou673

Reputation: 227

use a SqlParameter to do it as : 

string loadMainInfo = "SELECT * FROM Main_Information WHERE Username = @paramName"'; 
SqlParameter param1 = new SqlParameter () ; 
param1.ParameterName="@paramName";
param1.SqlDbType= SqlDbType.Varchar;
param1.Value= Globals.username;
cmd.Parameters.Add(param1);

Upvotes: 1

sbsd
sbsd

Reputation: 306

It looks like Globals.username may not have a value when you're referencing it for your query string, as the SQL error you're getting occurs when there is nothing following the = in the query.

I'd suggest using the debugger to look at the value of loadMainInfo just after its been set (or otherwise add the line MessageBox.Show(loadMainInfo); below).

Does the query string include the username value you expect?

Upvotes: 0

user9631542
user9631542

Reputation:

You could use String.Format

string loadMainInfo = String.Format(“SELECT * FROM Main_Information WHERE Username = {0}" ,Globals.username);

Upvotes: 0

Saliou673
Saliou673

Reputation: 227

You have make a wrong query, add the quote as this

string loadMainInfo = "SELECT * FROM Main_Information WHERE Username = '" + Globals.username + "'";

Upvotes: 0

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