C# 使用sql查询结果填充datagridview
我试图显示查询结果,但我一直得到一个空白的数据网格。C# 使用sql查询结果填充datagridview,c#,winforms,datagridview,C#,Winforms,Datagridview,我试图显示查询结果,但我一直得到一个空白的数据网格。 这就好像数据本身是不可见的 这是我的密码: private void Employee_Report_Load(object sender, EventArgs e) { string select = "SELECT * FROM tblEmployee"; Connection c = new Connection(); SqlDataAdapter dataAdapter = new SqlDataAd
这就好像数据本身是不可见的 这是我的密码:
private void Employee_Report_Load(object sender, EventArgs e)
{
string select = "SELECT * FROM tblEmployee";
Connection c = new Connection();
SqlDataAdapter dataAdapter = new SqlDataAdapter(select, c.con); //c.con is the connection string
SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dataAdapter);
DataTable table = new DataTable();
table.Locale = System.Globalization.CultureInfo.InvariantCulture;
dataAdapter.Fill(table);
bindingSource1.DataSource = table;
dataGridView1.ReadOnly = true;
dataGridView1.DataSource = bindingSource1;
}
此代码有什么问题?您不需要
bindingSource1
只需设置
dataGridView1.DataSource=table
尝试将您的DataGridView
绑定到DataTable
的DefaultView
:
dataGridView1.DataSource = table.DefaultView;
这是你的密码。下一步,忘记绑定源
var select = "SELECT * FROM tblEmployee";
var c = new SqlConnection(yourConnectionString); // 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];
如果将数据源设置为添加到表单但未使用的数据集,则可能会得到一个空白数据网格。如果您是根据上述代码以编程方式设置数据源,请将此设置为无。您可以尝试此示例,并始终检查连接字符串。,您可以使用此示例,也可以不使用bindingsource。您可以将数据加载到datagridview
private void Employee_Report_Load(object sender, EventArgs e)
{
var table = new DataTable();
var connection = "ConnectionString";
using (var con = new SqlConnection { ConnectionString = connection })
{
using (var command = new SqlCommand { Connection = con })
{
if (con.State == ConnectionState.Open)
{
con.Close();
}
con.Open();
try
{
command.CommandText = @"SELECT * FROM tblEmployee";
table.Load(command.ExecuteReader());
bindingSource1.DataSource = table;
dataGridView1.ReadOnly = true;
dataGridView1.DataSource = bindingSource1;
}
catch(SqlException ex)
{
MessageBox.Show(ex.Message + " sql query error.");
}
}
}
}
必须将属性表添加到DataGridView数据源
dataGridView1.DataSource = table.Tables[0];
如果您使用的是mysql,则可以使用此代码
string con = "SERVER=localhost; user id=root; password=; database=databasename";
private void loaddata()
{
MySqlConnection connect = new MySqlConnection(con);
connect.Open();
try
{
MySqlCommand cmd = connect.CreateCommand();
cmd.CommandText = "SELECT * FROM DATA1";
MySqlDataAdapter da = new MySqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
datagrid.DataSource = dt;
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
这被认为是最安全和错误的pron查询:
public void Load_Data()
{
using (SqlConnection connection = new SqlConnection(DatabaseServices.connectionString)) //use your connection string here
{
var bindingSource = new BindingSource();
string fetachSlidesRecentSQL = "select top (50) * from dbo.slides order by created_date desc";
using (SqlDataAdapter dataAdapter = new SqlDataAdapter(fetachSlidesRecentSQL, connection))
{
try
{
SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dataAdapter);
DataTable table = new DataTable();
dataAdapter.Fill(table);
bindingSource.DataSource = table;
recent_slides_grd_view.ReadOnly = true;
recent_slides_grd_view.DataSource = bindingSource;
}
catch (SqlException ex)
{
MessageBox.Show(ex.Message.ToString(), "ERROR Loading");
}
finally
{
connection.Close();
}
}
}
}
几年后,但这里是最简单的为其他情况下
String connectionString = @"Data Source=LOCALHOST;Initial Catalog=DB;Integrated Security=true";
SqlConnection cnn = new SqlConnection(connectionString);
SqlDataAdapter sda = new SqlDataAdapter("SELECT * FROM tblEmployee;", cnn);
DataTable data = new DataTable();
sda.Fill(data);
DataGridView1.DataSource = data;
使用
DataSet
是不必要的,而且DataTable
应该足够好了SQLCommandBuilder
也没有必要。在datagridview中绑定数据您可以“填充”一个DataTable
没有问题。不需要数据集
。它确实可以工作,但是数据集
是额外的开销,没有什么用处。@DonThomasBoyle在第二个示例代码中,使用的类是SqlServerCe
而不是SqlServer
。这可能会让人困惑,就像数据本身在我的案例中是不可见的一样,你看到datagridview中的列了吗?如果是,则查询不返回任何行!!我在SQLServer2008中检查了我的查询,它确实返回了employee Table的所有数据。已经有了可接受的答案,这提供了比您更多的信息。这是相当多余的。
String connectionString = @"Data Source=LOCALHOST;Initial Catalog=DB;Integrated Security=true";
SqlConnection cnn = new SqlConnection(connectionString);
SqlDataAdapter sda = new SqlDataAdapter("SELECT * FROM tblEmployee;", cnn);
DataTable data = new DataTable();
sda.Fill(data);
DataGridView1.DataSource = data;