C# 如何从数据库中选择C中的combobox来获得前3个值

我想选择组合框项目，并根据我在c 2010 express中的选择在datagridview上显示前3种可能性。我用C创建了数据库

    private void add_button_Click(object sender, EventArgs e)
    {          
        SqlConnection sqlcon = new SqlConnection();
        sqlcon.ConnectionString = @"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\Mystudies\C#\SQL Database\MakerSelectionDatabase.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";

        // insert Logic
        sqlcon.Open();

        SqlDataAdapter sda = new SqlDataAdapter("select * from makerinfo Where [Equipment Type] = '" + equipmenttype_combobox.Text.Trim() + "' and Plant='" + plant_combobox.Text.Trim() + "'", sqlcon);

        // I could not combine this code to combobox selection.
        // SqlDataAdapter eval = new SqlDataAdapter("select top 3 safety from makerinfo order by Safety desc", sqlcon);

        DataTable dt = new DataTable();
        SqlDataAdapter db = new SqlDataAdapter();
        sda.Fill(dt);

        datagridview.DataSource = dt;

        sqlcon.Close();
    }

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为什么不使用Select top૩ 并通过Saftey Desc在您的QueryTX中订购，以获得您的回复。您是否有任何示例链接或文档？我不知道如何将SQL查询与interface.SqlDataAdapterselect top结合起来运行૩ 来自makerinfo的安全性，其中[Equipment Type]='+equipmenttype_combobox.Text.Trim+'和Plant='+Plant_combobox.Text.Trim+'由Saftey desc、sqlcon订购；你试过这个吗？成功了：非常感谢。现在我将尝试获取所有行信息。