Question

我需要根据从下拉列表或文本框中输入或选择的值填充gridview。用户可能没有提及所有标准。我正在寻找一种根据用户的选择动态生成数据库查询的解决方案。

Answer 1

试试这个，您需要根据自己的条件更改代码。

            StringBuilder sqlQuery;
            SqlConnection con = new SqlConnection(@"Server=myServerName\myInstanceName;Database=myDataBase;User Id=myUsername;Password=myPassword; ");
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = con;
            string join = "";
            // textboxes
            if (TextBox_percentage.Text.Trim() != "")
            {
                sqlQuery.Append(join+" [percentage_column]>=@percentage");
                cmd.Parameters.AddWithValue("@percentage", TextBox_percentage.Text);
                join = " and ";

            }
            if (TextBox_cgpa.Text.Trim() != "")
            {
                sqlQuery.Append(join + " [cgpa_column]>=@cgpascore");
                cmd.Parameters.AddWithValue("@cgpascore", TextBox_cgpa.Text);
                join = " and ";
            }
            if (TextBox_experience.Text.Trim() != "")
            {
                sqlQuery.Append(join + " [experience_column]=@experience");
                cmd.Parameters.AddWithValue("@experience", TextBox_experience.Text);
                join = " and ";
            }
            // dropdowns, 'Default value'? Text/Value?
            if (dropdown_Industry.SelectedItem.Text != "Default Value")
            {

                sqlQuery.Append(join + " [Industry_column]=@Industry");
                cmd.Parameters.AddWithValue("@Industry", dropdown_Industry.SelectedItem.Text);
                join = " and ";
            }
            if (dropdown_Specialization.SelectedItem.Text != "Default Value")
            {

                sqlQuery.Append(join + " [Specialization _column]=@Specialization ");
                cmd.Parameters.AddWithValue("@Specialization ", dropdown_Specialization.SelectedItem.Text);
                join = " and ";
            }
            if (dropdown_Highest_degree.SelectedItem.Text != "Default Value")
            {

                sqlQuery.Append(join + " [Highest_degree_column]=@Highest_degree");
                cmd.Parameters.AddWithValue("@Highest_degree", dropdown_Highest_degree.SelectedItem.Text);
                join = " and ";
            }
            if (dropdown_College.SelectedItem.Text != "Default Value")
            {

                sqlQuery.Append(join + " [College_column]=@College");
                cmd.Parameters.AddWithValue("@College", dropdown_College.SelectedItem.Text);
                join = " and ";
            }
            if (dropdown_Location.SelectedItem.Text != "Default Value")
            {

                sqlQuery.Append(join + " [Location_column]=@Location");
                cmd.Parameters.AddWithValue("@Location", dropdown_Location.SelectedItem.Text);
                join = " and ";
            }

            cmd.CommandText = "Select * from table where " + sqlQuery.ToString();
            con.Open(); // try-catch-finally
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();
            da.Fill(dt);
            con.Close();
            gridView.DataSource = dt;
            gridView.DataBind();

动态生成基于的SQL查询

1 个答案: