从数据库读取数据到datatable，使用linq处理后，在datagridview显示

可以按照以下步骤操作：

1. 建立与数据库的连接并执行查询语句，将结果存储在DataTable中：

string connectionString = "your_connection_string";
string query = "SELECT * FROM your_table";
DataTable dataTable = new DataTable();
using (SqlConnection connection = new SqlConnection(connectionString))
{
    SqlCommand command = new SqlCommand(query, connection);
    SqlDataAdapter adapter = new SqlDataAdapter(command);
    adapter.Fill(dataTable);
}

2. 使用LINQ查询语句对DataTable进行处理，例如筛选出符合条件的数据：

var filteredData = from row in dataTable.AsEnumerable()
                   where row.Field<string>("column_name") == "condition_value"
                   select row;

3. 将处理后的数据绑定到DataGridView控件上：

dataGridView.DataSource = filteredData.ToList();

完整的代码示例：

string connectionString = "your_connection_string";
string query = "SELECT * FROM your_table";
DataTable dataTable = new DataTable();
using (SqlConnection connection = new SqlConnection(connectionString))
{
    SqlCommand command = new SqlCommand(query, connection);
    SqlDataAdapter adapter = new SqlDataAdapter(command);
    adapter.Fill(dataTable);
}

var filteredData = from row in dataTable.AsEnumerable()
                   where row.Field<string>("column_name") == "condition_value"
                   select row;

dataGridView.DataSource = filteredData.ToList();