gowtham gowtham - 3 months ago 17
ASP.NET (C#) Question

Need to find ID number from database using string in c#

I need to get data from label which i had got back from previous page using Sessions from that label i need to use it to find ID for that data for example if Label contain word 'IT' it need to find its ID in database D_ID=5 code is given below

public partial class FinalFeedback1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
GetDataFromSession();
GetDID();
AddDynamicLabels();
}

public void GetDID()
{
var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
SqlDataReader myReader1 = null;
string depart = "select D_ID from Department where D_Name= " + Label8.Text + "";
SqlCommand cmd1 = new SqlCommand(depart, connection);
myReader1 = cmd1.ExecuteReader(); // i am getting error here "Invalid column name 'IT'"
while (myReader1.Read())
{
Label9.Text = myReader1["D_ID"].ToString();
}
}
}
public void AddDynamicLabels()
{
var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
SqlDataReader myReader2 = null;
string CmdString = "Select Q_ID,Question_Data FROM QuestionTable where D_ID=" + Label9.Text + "";
SqlCommand cmd = new SqlCommand(CmdString, connection);
myReader2 = cmd.ExecuteReader();
while (myReader2.Read())
{
QID1.Text = myReader2["Q_ID"].ToString();
if (QID1.Text == ("1"))
{
Question1.Text = myReader2["Question_Data"].ToString();
}
else if (QID1.Text ==("2"))
{
Question2.Text = myReader2["Question_Data"].ToString();
}
else if (QID1.Text == ("3"))
{
Question3.Text = myReader2["Question_Data"].ToString();
}
else if (QID1.Text == ("4"))
{
Question4.Text = myReader2["Question_Data"].ToString();
}
else if (QID1.Text == ("5"))
{
Question5.Text = myReader2["Question_Data"].ToString();
}
}
}
}

private void GetDataFromSession()
{
Label2.Text = Session["SNL"].ToString();
Label4.Text = Session["SNB"].ToString();
Label6.Text = Session["EMPID"].ToString();
Label8.Text = Session["DNAME"].ToString();
}


}

Answer

Change this line.

string depart = "select D_ID from Department where D_Name= " + Label8.Text + "";

to this line

string depart = "select D_ID from Department where D_Name= '" + Label8.Text + "'";

See the single quotes in the second line. Your string value is not in single quotes and this is the reason.

EDIT: Your code is open for SQL Injection Attack. You should use the SqlParameter instead of concatenating the query.

For More reading you can use this link: http://www.w3schools.com/sql/sql_injection.asp

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