DataGridView.DataSource不会将三个或更多datagridview绑定在一起

Question

我有3 DataGridView如下

1. dataGridViewTASKLIST
2. dataGridView_USER_ROLES
3. dataGridViewProjects

这3个网格用于不同目的。我试图使用sqlDataAdapter和DataTable绑定（使用BindingSource）来自3个不同表，Table1，Table2，Table3（Inside数据库）的数据。运行程序后，只有第一个网格（dataGridViewTASKLIST）填充了行和列，其余两个网格都是空的。

我的代码如下：

Console.WriteLine("Binding 1st Grid");
BindingSource bn = new BindingSource();

bn.DataSource = this.dbCommon.getDataTableAsResult("select * from taskTable");
dataGridViewTASKLIST.DataSource = bn;

Console.WriteLine("Binding 2nd Grid");
BindingSource bn1 = new BindingSource();

bn1.DataSource = this.dbCommon.getDataTableAsResult("select * from userTable");
dataGridView_USER_ROLES.DataSource = bn1;

Console.WriteLine("Binding 3rd Grid");
BindingSource bn2 = new BindingSource();

bn2.DataSource = this.dbCommon.getDataTableAsResult("select * from projectTable");
dataGridViewProjects.DataSource = bn2;

其中dbCommon是类DatabaseClass的对象，getDataTableAsResult（）是databaseClass中的一个方法

public DataTable getDataTableAsResult(string cmd)
{
    sqlDatatable = new DataTable();
    try
    {
        if (this.openConnection())
        {
            sqlAdapter = new SqlDataAdapter(cmd, this.sqlConn);
            sqlAdapter.Fill(sqlDatatable);
        }

     }
     catch { }
     finally
     {
        this.closeConnection();
     }
     return sqlDatatable;
}