[英]How to populate a DataGridView by selecting any table from combo box
I have used the following code for displaying names of my SQL db tables in a combo box. 我使用以下代码在组合框中显示我的SQL数据库表的名称。
Now I want that when I click on any of these table names from the combo box, my DGV populates with that table's contents. 现在我希望当我从组合框中点击这些表名中的任何一个时,我的DGV会填充该表的内容。
private void Form1_Load(object sender, EventArgs e)
{
String strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true";
SqlConnection con = new SqlConnection(strConnection);
try
{
con.Open();
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.Connection = con;
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "Select table_name from information_schema.tables";
SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);
DataTable dtRecord = new DataTable();
sqlDataAdap.Fill(dtRecord);
comboBox1.DataSource = dtRecord;
comboBox1.DisplayMember = "TABLE_NAME";
con.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Then I used the following code for populating my DGV but it's not working; 然后我使用以下代码填充我的DGV,但它不起作用; please help.
请帮忙。
private void PopulateGridView()
{
String strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true";
SqlConnection con = new SqlConnection(strconnection);
try
{
con.Open();
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.Connection = con;
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "select * from " + comboBox1.SelectedText;
SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);
DataTable dtRecord = new DataTable();
sqlDataAdap.Fill(dtRecord);
dataGridView1.AutoGenerateColumns = true;
dataGridView1.DataSource = dtRecord;
dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
con.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox1.SelectedValue != null)
{
PopulateGridView(comboBox1.SelectedValue.ToString());
}
}
Try this: 尝试这个:
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox1.SelectedValue != null)
{
string strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true";
SqlConnection con = new SqlConnection(strconnection);
try
{
con.Open();
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.Connection = con;
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "select * from " + comboBox1.SelectedValue;
SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);
DataTable dtRecord = new DataTable();
sqlDataAdap.Fill(dtRecord);
dataGridView1.AutoGenerateColumns = true;
dataGridView1.DataSource = dtRecord;
dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
con.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
just try this: update your code in the Form Load with below: 试试这个:在下面的表单加载中更新你的代码:
private void Form1_Load(object sender, EventArgs e)
{
String strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true";
SqlConnection con = new SqlConnection(strConnection);
try
{
con.Open();
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.Connection = con;
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "Select table_name from information_schema.tables";
SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);
DataTable dtRecord = new DataTable();
sqlDataAdap.Fill(dtRecord);
comboBox1.DataSource = dtRecord;
comboBox1.DisplayMember = "table_name";
comboBox1.ValueMember = "table_name";
con.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
so basically you have added one extra line comboBox1.ValueMember = "table_name";
所以基本上你添加了一个额外的行
comboBox1.ValueMember = "table_name";
and make your PopulateGridView method like this: 并使你的PopulateGridView方法像这样:
private void PopulateGridView(string tblName)
{
String strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true";
SqlConnection con = new SqlConnection(strConnection);
try
{
con.Open();
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.Connection = con;
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "select * from " + tblName;
SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);
DataTable dtRecord = new DataTable();
sqlDataAdap.Fill(dtRecord);
dataGridView1.AutoGenerateColumns = true;
dataGridView1.DataSource = dtRecord;
dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
con.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
it has to work. 它必须工作。 Also, I see, you are creating
SqlConnection
object everywhere, including SqlCommand
and SqlDataAdapter
. 另外,我知道,你到处都在创建
SqlConnection
对象,包括SqlCommand
和SqlDataAdapter
。
try to wrap them up in static methods ie 尝试用静态方法包装它们,即
- public static SqlConnection OpenConnection()
- public static DataTable ExecuteSelectQuery(string Query)
- public static bool ExecuteModifyQuery(string Query)
try to write as less amount of code as you can. 尝试尽可能少地编写代码。
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