如何使用int ID为null的条件过滤数据表

问题描述

我有gridview：

I have gridview:

GridViewName.DataSource = table;

表值：

table values:

string myConnection = ConfigurationManager.ConnectionStrings["vizitka"].ToString();
string Query_sel = MySqlString;
MySqlConnection conDataBase = new MySqlConnection(myConnection);
MySqlCommand cmdDataBase_sel = new MySqlCommand(Query_sel, conDataBase);
  try
  {
     MySqlDataAdapter sda = new MySqlDataAdapter();
     sda.SelectCommand = cmdDataBase_sel;
     DataTable dbdataset = new DataTable();
     sda.Fill(dbdataset);
     BindingSource bSource = new BindingSource();
     bSource.DataSource = dbdataset;
     TableName.DataSource = bSource;
     sda.Update(dbdataset);
   }
     catch (Exception ex)
     {
        MessageBox.Show(ex.Message);
     }

我得到的价值观：

[]



然后，我正在添加新行到表：

I'm getting Values:
https://i.stack.imgur.com/G561j.jpg[^]

then, I'm adding new row to table:

DataRow newRow = table.NewRow();
table.Rows.Add(newRow);

并获取带有空单元格的值（ID也为空，对我有好处）：

[]

然后：

and getting values with empty cells (also ID is empty and it's good for me):
https://i.stack.imgur.com/quGck.jpg>[^]
then:

GridViewName.DataSource = table;

一切都很好，但随后如果我想从表中删除这个新创建的行，我不能。我正在尝试过滤并再次绑定GridViewName。



我尝试过：

all is good, but then if I want to delete from table this new created row, I cannot. I'm trying to filter and bind again GridViewName.

What I have tried:

DataView view = new DataView(table);
view.RowFilter = "CONVERT(id, System.String) = null or CONVERT(id, System.String) = ''";
Console.WriteLine(view);

但是我得到空表。为什么?????

but I'm getting empty table. why?????

推荐答案

view.RowFilter = "ID IS NULL";

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