title: Can not Insert the NULL value into Auto Increment PrimaryKey Column
body: <p>I have created the table <code>Items</code> in C# database as the property of the primary key is AutoIncrement=True, AutoIncrementStep=1, Unique=True, AutoIncrementSeeds=0;</p>
  
  <pre><code>CREATE TABLE [dbo].[Items] 
  (
      [item_id]       INT          NOT NULL,
      [item_name]     VARCHAR (50) NULL,
      [item_model]    VARCHAR (50) NULL,
      [item_price]    VARCHAR (50) NULL,
      [item_quantity] VARCHAR (50) NULL,
      [entry_date]    VARCHAR (50) NULL,
      [user_id]       VARCHAR (50) NULL,
  
      PRIMARY KEY CLUSTERED ([item_id] ASC)
  );
  </code></pre>
  
  <p>and I am inserting data into the <code>Items</code> table using this code:</p>
  
  <pre><code>string query = @"Insert into Items(item_name, item_model, item_price, item_quantity, entry_date, user_id)" +
                  "VALUES(@name, @model, @price, @quantity, @date, @user)";
  
  using (SqlConnection c = new SqlConnection(Properties.Settings.Default.Database1ConnectionString))
  {
      try
      {
          c.Open();
  
          if (c.State == ConnectionState.Open)
          {
              SqlCommand command1 = new SqlCommand(query, c);
  
              command1.Parameters.AddWithValue("@name", name.Text.ToString());
              command1.Parameters.AddWithValue("@model", model.Text.ToString());
              command1.Parameters.AddWithValue("@price", price.Text.ToString());
              command1.Parameters.AddWithValue("@quantity", quantity.Text.ToString());
              command1.Parameters.AddWithValue("@date", dateTimePicker1.Text.ToString());
              command1.Parameters.AddWithValue("@user", added_by.Text.ToString());
  
              int k = command1.ExecuteNonQuery();
  
              if (k &gt; 0)
              {
                  MessageBox.Show("Data Added Successfully");
                  c.Close();
                  return;
              }
              else 
              {
                  MessageBox.Show("Data was not added successfully - try again later");
                  c.Close();
                  return;
              }
          }
      }
      catch (Exception ex)
      {
          MessageBox.Show("Failed To Open Connection :." + ex);
          return;
      }
  }
  </code></pre>
  
  <p>When I run code and try to insert data I get error</p>
  
  <blockquote>
    <p>Cannot Insert NULL value into column 'item_id' table</p>
  </blockquote>