Question

我想在我的程序中添加搜索功能。有一个具有此功能的类：

public DataTable Search()
        {
            string SQL = "Select * from Customer where " + mField + " like '%" + mValue + "%'";
            DataTable dt = new DataTable();
            dt = dm.GetData(SQL);
            return (dt);

        }

mField和mValue有setter和getter属性。 DM是类DataManagement的对象，其方法为GetData：

public DataTable GetData(string SQL)
    {
        SqlCommand command = new SqlCommand();
        SqlDataAdapter dbAdapter = new SqlDataAdapter();
        DataTable DataTable = new DataTable();

        command.Connection = clsConnection.GetConnection();
        command.CommandText = SQL;
        dbAdapter.SelectCommand = command;
        dbAdapter.Fill(DataTable);
        return (DataTable);
    }

搜索功能目前实现如下：

private void btnfind_Click(object sender, EventArgs e)
    {
       //cust is the object of class customer//
        if (tbCustName.Text != "")
        {
            cust.Field="CustName";
            cust.Value = tbCustName.Text;
        }
        else if (tbAddress.Text != "")
        {
            cust.Value = tbAddress.Text;
            cust.Field="Address";
        }
        else if (tbEmail.Text != "")
        {
            cust.Value = tbEmail.Text;
            cust.Field="Email";
        }
        else if (tbCell.Text != "")
        {
            cust.Value = tbCell.Text;
            cust.Field = "Cell";
        }

        DataTable dt = new DataTable();
        dt = cust.Search();
        dgCustomer.DataSource = dt;
        RefreshGrid();
    }

    private void RefreshGrid()
    {
        DataTable dt = new DataTable();
        dt = cust.GetCustomers();
        dgCustomer.DataSource = dt;
    }

这不起作用。我不知道为什么。请帮忙。

Answer 1

在DataBind()方法中添加RefreshGrid()语句，让您的新结果真正显示在网格上。

private void RefreshGrid()
{
    DataTable dt = cust.GetCustomers();
    dgCustomer.DataSource = dt;
    dgCustomer.DataBind();
}

考虑修改你的其他方法：

您的ad-hoc SQL存在SQL注入漏洞。停止一切，直到你解决它！

btnfind_Click无需最终调用cust.Search()两次。

private void btnfind_Click(object sender, EventArgs e)
{
    //<snip>
    // no need to do all this twice.
    //  DataTable dt = new DataTable();
    // dt = cust.Search();
    // dgCustomer.DataSource = dt;
    RefreshGrid();

}

Answer 2

您的RefreshGrid方法会覆盖您在DataSource中设置的btnfind_Click ...请勿拨打电话，只需拨打DataBind

private void btnfind_Click(object sender, EventArgs e)
{
    ...

    DataTable dt = cust.Search();
    dgCustomer.DataSource = dt;
    dgCustomer.DataBind();

}

顺便说一句，如果您立即将其设置为DataTable的结果，则无需为dt指定新的cust.Search ...您只需为其创建实例什么都没有（我在上面的代码中修复了它）

将搜索结果绑定到数据网格

2 个答案: