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Old November 27th, 2006, 07:33 AM
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Default Checking for duplicate primary key in Access

Hi folks,

I am working with ASP.NET 2.0 and am having a headache trying to check for an existing primary key in an Access database. I have a web form that will be used to add a new record of staff details. Currently there are several thousand members of staff that are stored in the database, each has a unique primary key entitled staff_id. This is simply a 4 digit number (for example, 2345), if I add a record with an existing staff ID it will post back an asp.net error. I am attempting (and rather badly) to write a script that will check for the existing field staff_id if the user enters an existing ID number in the web form textbox. This is what I have come up with so far but it simply throws back this error.

Error 2 Operator '==' cannot be applied to operands of type 'method group' and 'string' C:\Inetpub\wwwroot\CourseList\Admin\addStaff.aspx 23 12 C:\...\CourseList
I am working with C# and trying to convert a piece of VB.Net code. I have done record checks before in classic asp and have never had a problem but now I am lost. This is the script I have written.

<script runat="server">

protected void bntClick_Click(object sender, EventArgs e)


           Boolean ValidRecord;

           string connStaff = ConfigurationSettings.AppSettings["ConnStaff"];

           OleDbConnection conn = new OleDbConnection(connStaff);


           string sqlString = "SELECT COUNT(*) FROM staff WHERE staff_id = '" + txtstaffID.Text + "'";

           OleDbCommand myCommand = new OleDbCommand(sqlString, conn);

           object qryValue = myCommand.ExecuteScalar();

           if(qryValue.ToString == txtstaffID.Text)


                  Label1.Text = "This is a duplicate record";

                  ValidRecord = false;





                  ValidRecord = true;



 Any help with this would be greatly appreciated.

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Old November 29th, 2006, 12:11 PM
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Hi ,
The line
 object qryValue = myCommand.ExecuteScalar();

is where problem lies.

u must store the result of myCommand.ExecuteScalar(); as string as

string qryvalue = (string)myCommand.ExecuteScalar();
the check it.

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Old November 29th, 2006, 12:19 PM
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You forgot the parentheses on the method call ToString

 if(qryValue.ToString == txtstaffID.Text)

should be

 if(qryValue.ToString() == txtstaffID.Text)

A bit confusing error message, I must say... ;)

Imar Spaanjaars
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Author of ASP.NET 2.0 Instant Results and Beginning Dreamweaver MX / MX 2004
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