title: Button Click throws System.NullReferenceException
body: <p><strong>System.NullReferenceException: Object reference not set to an instance of an object.</strong></p>
  
  <p>When clicking the button, i recieve that error. .<br>
  <strong>Form1 Class:</strong></p>
  
  <pre><code>private void button1_Click(object sender, EventArgs e)
      {
          string connectionString = ConfigurationManager.ConnectionStrings["modelConnectionString"].ConnectionString;
          SqlConnection sqlConnection = new SqlConnection(connectionString);
          sqlConnection.Open();
          SqlCommand connect = new SqlCommand("SELECT COUNT(*) From Users WHERE UserName = @user AND Password = @pass", sqlConnection);
          SqlParameter username = connect.Parameters.AddWithValue("@user", userName.Text);
          SqlParameter password = connect.Parameters.AddWithValue("@pass", passWord.Text);
  
          if ((int)connect.ExecuteScalar() == 1)
          {
              accessPic.BackgroundImage = Res.Accepted;
          }
          else
          {
              accessPic.BackgroundImage = Res.Denied;
          }
          sqlConnection.Close();
      }
  </code></pre>
  
  <p><strong>Form1.Designer</strong></p>
  
  <pre><code>        // 
          // button1
          // 
          this.button1.Location = new System.Drawing.Point(95, 90);
          this.button1.Name = "button1";
          this.button1.Size = new System.Drawing.Size(75, 25);
          this.button1.TabIndex = 8;
          this.button1.Text = "button1";
          this.button1.UseVisualStyleBackColor = true;
          this.button1.Click += new System.EventHandler(this.button1_Click);
  </code></pre>