Forms Data Controls :: Using Gridview To Create Searchable History - C#

I'm looking to use a gridview to create a basic search page for my website. On the page I have the following:

1.) A dropdown list with the search parameters
2.) Textbox where the user enters their search
3.) A Submit button.

In the submitclick, I want the gridview to display the contents of my database, but only the items that match what the user has entered into the textbox based on the parameter they chose from the dropdown list. I have the following code:

SqlConnection SearchConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["LandRover"].ToString());
SqlCommand SearchCommand = new SqlCommand("SELECT * FROM ORDERLINE WHERE " + ddlSearch.SelectedValue.ToString() + " = @Search", SearchConnection);
SearchCommand.Parameters.Add("@Search", SqlDbType.NVarChar).Value = txtSearch.Text;
SearchConnection.Open();
SqlDataReader SearchReader = SearchCommand.ExecuteReader();
if (SearchReader.HasRows)
{
grvHistory.DataSource = SearchReader;
grvHistory.Visible = true;
grvHistory.DataBind();
}

I'm code this in C#