c# dropdownlist避免多个insert语句？

string selectedValue = dropdownlist.SelectedValue;
string insertQuery = "INSERT INTO table_name (column_name) VALUES (@value)";

using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    
    using (SqlCommand command = new SqlCommand(insertQuery, connection))
    {
        command.Parameters.AddWithValue("@value", selectedValue);
        command.ExecuteNonQuery();
    }
}

List<string> selectedValues = new List<string>();
foreach (ListItem item in dropdownlist.Items)
{
    if (item.Selected)
    {
        selectedValues.Add(item.Value);
    }
}

string insertQuery = "INSERT INTO table_name (column_name) VALUES (@value)";
using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    
    using (SqlCommand command = new SqlCommand(insertQuery, connection))
    {
        foreach (string value in selectedValues)
        {
            command.Parameters.Clear();
            command.Parameters.AddWithValue("@value", value);
            command.ExecuteNonQuery();
        }
    }
}

// 创建存储过程
CREATE PROCEDURE InsertData
    @value varchar(50)
AS
BEGIN
    INSERT INTO table_name (column_name) VALUES (@value)
END

// 调用存储过程
string selectedValue = dropdownlist.SelectedValue;
string storedProcedureName = "InsertData";

using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    
    using (SqlCommand command = new SqlCommand(storedProcedureName, connection))
    {
        command.CommandType = CommandType.StoredProcedure;
        command.Parameters.AddWithValue("@value", selectedValue);
        command.ExecuteNonQuery();
    }
}