Question

您好，当我单击按用户名搜索时，我试图添加一个搜索按钮，只显示我搜索过的那个

 private void Update_Click(object sender, EventArgs e)
    {
        conect.Open();
        OleDbCommand command = conect.CreateCommand();
        command.CommandType = CommandType.Text;
        command.CommandText = "select * from Sign_Up where UserName='"+Username.Text+"'";
        command.ExecuteNonQuery();
        DataTable dt = new DataTable();
        OleDbDataAdapter da = new OleDbDataAdapter();
        da.Fill(dt);
        dataGridView1.DataSource = dt;
        conect.Close();
    }

这是我的程序图片Pic 这是我的错误`System.InvalidOperationException：'在调用'Fill'之前，尚未初始化SelectCommand属性。'

使用此代码da.Fill（dt）;

Answer 1

您需要将SelectCommand的{{1}}属性设置为

OleDbDataAdapter

或者您可以通过构造函数传递命令

conect.Open();
OleDbCommand command = conect.CreateCommand();
command.CommandType = CommandType.Text;
command.CommandText = "select * from Sign_Up where UserName='"+Username.Text+"'";
//command.ExecuteNonQuery(); no need to execute command manually
DataTable dt = new DataTable();
OleDbDataAdapter da = new OleDbDataAdapter();
da.SelectCommand = command; //add this line
da.Fill(dt);
dataGridView1.DataSource = dt;
conect.Close();

c＃Windows窗体（尝试在表中添加搜索按钮）

1 个答案: