Populating a Combo Box

Question

I created a Windows Form, with a ComboBox, and a Local Database in Visual Studio 2010. The database has a table with a column whose rows I want to list in the combo box. How can I achieve this?

I tried adding a data source with the column I am interested in through the IDE, but it did not work.

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I created a Windows Forms Application with a Windows Form containing a ComboBox.

                                                           

I created a Local Database containing a Table with a single column and three test rows.

                                                             

I added a data source containing the column I am interested in.

  

Finally, I bound the combo box to the data source, but the result is strange.

                   

Answer 1

This is the raw code to accomplish what you are asking:

string strCmd = "";
string strConn = "";
SqlConnection sqlConn = new SqlConnection();
SqlCommand sqlCmd = new SqlCommand(strCmd, sqlConn);
SqlDataReader sqlRdr = new SqlDataReader();

sqlConn.Open();

if (comboBox1.Items.Count > 0)
   comboBox1.Items.Clear();
sqlRdr = sqlCmd.ExecuteReader();

while (sqlRdr.Read())
   comboBox1.Items.Add(sqlRdr[0].ToString());

sqlRdr.Close();
sqlConn.Close();

There are a few things you will need to wire-up first though. The first one is this:

string strCmd = "";  // Insert your SQL statement here.

Second:

string strConn = "";  // Your db connection string goes here.

Thirdly:

if (comboBox1.Items.Count > 0)  // You don't have to use this. It just checks to see 
   comboBox1.Items.Clear();     // if there is anything in the combobox and clears it.

Lastly, since you are making something that handles interactions between your form and a database, I strongly suggest that you use SqlParameters to prevent SQL Injection attacks.