[英]C# Combobox and DataGridView
我有一个组合框,它从一个选择中检索数据,一个 datagridview 从另一个查询中检索数据。 我想使用组合框值过滤数据网格视图。 我正在尝试一切,但没有任何效果。 能否请你帮忙? 此外,为什么当我声明 dataview=((DataTable)datagridview.datasource.defaultview(combobox_SelectedIndexChanged 中的第一行)时,我看不到组合框中的任何值,而是看到 System Data DataRowView 但第一个问题对我来说更重要
private void Form5_Load(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection(@"Data Source=xxxxx;Initial Catalog=xxxxx;Integrated Security=True;");
conn.Open();
SqlCommand sc = new SqlCommand(" SELECT id, customername+' - '+cast(inserted as varchar(19)) as targ FROM bf where customername>'a' order by customername asc, inserted desc ", conn);
SqlDataReader reader;
reader = sc.ExecuteReader();
DataTable dt = new DataTable();
dt.Columns.Add("id", typeof(string));
dt.Columns.Add("targ", typeof(string));
dt.Load(reader);
comboBox1.ValueMember = "id";
comboBox1.DisplayMember = "targ";
comboBox1.DataSource = dt;
conn.Close();
var select = "SELECT [id],[CustomerName[email],[Capital] FROM baf order by id desc";
var c = new SqlConnection("Data Source=xxxxxx;Initial Catalog=xxxxx;Integrated Security=True;"); // Your Connection String here
var dataAdapter = new SqlDataAdapter(select, c);
var commandBuilder = new SqlCommandBuilder(dataAdapter);
var ds = new DataSet();
dataAdapter.Fill(ds);
dataGridView1.ReadOnly = true;
dataGridView1.DataSource = ds.Tables[0];
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
//var dataView = ((DataTable)dataGridView1.DataSource).DefaultView;
// if (comboBox1.Text == "Remove filter")
// {
// dataView.RowFilter = string.Empty;
// }
// else
// {
// //dataView.RowFilter = "id = {comboBox1.Text}";
// }
//}
}
为此,您需要正确使用 BindingSource。 下面是完整的工作示例。 要试验它,您需要如下:
我希望这会让你过得很好。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace WinFormQ
{
public partial class Q1 : Form
{
public Q1()
{
InitializeComponent();
}
BindingSource bs;
private void Q1_Load(object sender, EventArgs e)
{
// SqlConnection conn = new SqlConnection(@"Data Source=xxxxx;Initial Catalog=xxxxx;Integrated Security=True;");
// conn.Open();
// SqlCommand sc = new SqlCommand(" SELECT id, customername+' - '+cast(inserted as varchar(19)) as targ FROM bf where customername>'a' order by customername asc, inserted desc ", conn);
// SqlDataReader reader;
//
// reader = sc.ExecuteReader();
DataTable dt = new DataTable();
dt.Columns.Add("id", typeof(string));
dt.Columns.Add("targ", typeof(string));
// dt.Load(reader);
dt.Rows.Add("1", "Targ-1"); // example code - remove
dt.Rows.Add("2", "Targ-2"); // example code - remove
dt.Rows.Add("3", "Targ-3"); // example code - remove
dt.Rows.Add("4", "Targ-4"); // example code - remove
comboBox1.ValueMember = "id";
comboBox1.DisplayMember = "targ";
comboBox1.DataSource = dt;
// var select = "SELECT [id],[CustomerName[email],[Capital] FROM baf order by id desc";
// var c = new SqlConnection("Data Source=xxxxxx;Initial Catalog=xxxxx;Integrated Security=True;"); Your Connection String here
// var dataAdapter = new SqlDataAdapter(select, c);
// var commandBuilder = new SqlCommandBuilder(dataAdapter);
DataSet ds = new DataSet();
DataTable bf = new DataTable("BF");
bf.Columns.Add("id", typeof(string)); // example code - remove
bf.Columns.Add("CustomerName", typeof(string)); // example code - remove
bf.Columns.Add("Email", typeof(string)); // example code - remove
bf.Columns.Add("Capital", typeof(string)); // example code - remove
ds.Tables.Add(bf);
bs = new BindingSource(ds, "BF");
// dataAdapter.Fill(bf);
bf.Rows.Add("1", "Customer-1", "Email-1", "Capital-1"); // example code - remove
bf.Rows.Add("1", "Customer-2", "Email-2", "Capital-1"); // example code - remove
bf.Rows.Add("2", "Customer-3", "Email-3", "Capital-2"); // example code - remove
bf.Rows.Add("3", "Customer-4", "Email-4", "Capital-3"); // example code - remove
bf.Rows.Add("3", "Customer-5", "Email-5", "Capital-3"); // example code - remove
bf.Rows.Add("3", "Customer-6", "Email-6", "Capital-3"); // example code - remove
bf.Rows.Add("4", "Customer-7", "Email-7", "Capital-4"); // example code - remove
dataGridView1.ReadOnly = true;
dataGridView1.DataSource = bs;
this.comboBox1.SelectedIndexChanged += new EventHandler(comboBox1_SelectedIndexChanged);
}
void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox1.Text == "Remove filter")
{
bs.RemoveFilter();
}
else if (comboBox1.SelectedValue == null)
{
bs.RemoveFilter();
}
else
{
bs.Filter = "id = " + comboBox1.SelectedValue;
}
}
}
}
我以这种方式解决了(可能不是最优雅的,但它确实有效):
private void Form5_Load(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection(@"Data Source=xxxxx;Initial Catalog=xxxxx;Integrated Security=True;");
conn.Open();
SqlCommand sc = new SqlCommand(" SELECT id, customername+' - '+cast(inserted as varchar(19)) as targ FROM baf where customername>'a' order by customername asc, inserted desc ", conn);
SqlDataReader reader;
reader = sc.ExecuteReader();
DataTable dt = new DataTable();
dt.Columns.Add("id", typeof(string));
dt.Columns.Add("targ", typeof(string));
dt.Load(reader);
comboBox1.ValueMember = "id";
comboBox1.DisplayMember = "targ";
comboBox1.DataSource = dt;
conn.Close();
var select = "SELECT [id],[CustomerName], [email],[CapActual] FROM baf order by id desc";
var c = new SqlConnection("Data Source=xxxx;Initial Catalog=xxxxx;Integrated Security=True;"); // Your Connection String here
var dataAdapter = new SqlDataAdapter(select, c);
var commandBuilder = new SqlCommandBuilder(dataAdapter);
var ds = new DataSet();
var bf = new DataTable("BF");
ds.Tables.Add(bf);
dataAdapter.Fill(bf);
dataGridView1.ReadOnly = true;
dataGridView1.DataSource = bf;
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
var select = "SELECT [id],[CustomerName],[email],[CapActual] FROM baf where id="+comboBox1.SelectedValue+" order by id desc";
var c = new SqlConnection("Data Source=xxxxx;Initial Catalog=xxxxxx;Integrated Security=True;"); // Your Connection String here
var dataAdapter = new SqlDataAdapter(select,c);
var commandBuilder = new SqlCommandBuilder(dataAdapter);
var ds = new DataSet();
var bf = new DataTable("BF");
ds.Tables.Add(bf);
dataAdapter.Fill(bf);
dataGridView1.ReadOnly = true;
dataGridView1.DataSource = bf;
}
}
}
对于有兴趣了解如何使相关代码成功运行的观众,我在下面提供了解决方案。 为了做好实验准备,数据是硬编码的,需要根据实际情况进行修改。
DataView dataView = null; // <<< Difference #1
private void Form1_Load(object sender, EventArgs e)
{
var dt = new DataTable();
dt.Columns.Add("id", typeof(string));
dt.Columns.Add("targ", typeof(string));
dt.Rows.Add("1", "Targ-1"); // example code - remove
dt.Rows.Add("2", "Targ-2"); // example code - remove
dt.Rows.Add("3", "Targ-3"); // example code - remove
dt.Rows.Add("4", "Targ-4"); // example code - remove
comboBox1.ValueMember = "id";
comboBox1.DisplayMember = "targ";
comboBox1.DataSource = dt;
var bf = new DataTable("BF");
bf.Columns.Add("id", typeof(string)); // example code - remove
bf.Columns.Add("CustomerName", typeof(string)); // example code - remove
bf.Columns.Add("Email", typeof(string)); // example code - remove
bf.Columns.Add("Capital", typeof(string)); // example code - remove
bf.Rows.Add("1", "Customer-1", "Email-1", "Capital-1"); // example code - remove
bf.Rows.Add("1", "Customer-2", "Email-2", "Capital-1"); // example code - remove
bf.Rows.Add("2", "Customer-3", "Email-3", "Capital-2"); // example code - remove
bf.Rows.Add("3", "Customer-4", "Email-4", "Capital-3"); // example code - remove
bf.Rows.Add("3", "Customer-5", "Email-5", "Capital-3"); // example code - remove
bf.Rows.Add("3", "Customer-6", "Email-6", "Capital-3"); // example code - remove
bf.Rows.Add("4", "Customer-7", "Email-7", "Capital-4"); // example code - remove
dataGridView1.ReadOnly = true;
dataGridView1.DataSource = bf;
dataView = bf.DefaultView; // <<< Difference #2
this.comboBox1.SelectedIndexChanged += new EventHandler(comboBox1_SelectedIndexChanged); // <<< Difference #3
}
void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox1.Text == "Remove filter")
{
dataView.RowFilter = string.Empty;
}
else
{
dataView.RowFilter = string.Format("id = '{0}'", comboBox1.SelectedValue); // <<< Difference #4
}
}
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