I need some help to complete this. I have searched and tried several ways but is not enetring in my head yet. It is not homework! I am a self learner.
I managed to populate a grid selecting the table from a dropdown:
private void radDropDownList1_SelectedIndexChanged(object sender, Telerik.WinControls.UI.Data.PositionChangedEventArgs e)
{
if (radDropDownList1.SelectedIndex > 0)
{
radGridView1.Visible = true;
label8.Text = radDropDownList1.SelectedValue.ToString();
DataTable dt = new DataTable();
var selectedTable = radDropDownList1.SelectedValue; //Pass in the table name
string query = #"SELECT * FROM " + selectedTable;
using (var cn = new SqlConnection(connString))
{
cn.Open();
try
{
SqlCommand cmd = new SqlCommand(query, cn);
using (var da = new SqlDataAdapter(cmd))
{
da.Fill(dt);
}
}
catch (SqlException ex)
{
//MessageBox.Show(ex.StackTrace);
}
}
radGridView1.DataSource = dt;
}
Now I am trying to write the event to update the sql table using the grid as datasource:
private void radGridView1_CellEndEdit(object sender, Telerik.WinControls.UI.GridViewCellEventArgs e)
{
DataTable dt = (DataTable)radGridView1.DataSource;
DataSet ds = new DataSet();
ds.Tables[0] = dt;
try
{
//**I am lost here!**
}
catch
{
}
}
Could you please help? How can I now update the sql table?
I don't really like the way you are managing the updates but... this code here will send an update statement:
using (var cn = new SqlConnection(connString))
{
cn.Open();
try
{
SqlCommand cmd = new SqlCommand("UPDATE YourTable SET Column = #Parm1 WHERE Col = #Parm2", cn);
var parm1 = cmd.CreateParameter("Parm1");
parm1.Value = "SomeValue";
var parm2 = cmd.CreateParameter("Parm2");
parm2.Value = "SomeOtherValue";
cmd.Parameters.Add(parm1);
cmd.Parameters.Add(parm2);
int rowsAffected = cmd.ExecuteNonQuery();
}
catch (SqlException ex)
{
//MessageBox.Show(ex.StackTrace);
}
}
Related
I want to display data in a datagrid based on value selected in a ComboBox but my datatable function returns null and nothing is displayed in the datagrid.
public DataTable ReadData(User user)
{
using (SqlConnection db = new SqlConnection(AppConnect.Connection))
{
string query = "SELECT moduleCode,moduleName,modCredits,modHrsLeft FROM [Module] WHERE userName=#userName";
try
{
using (SqlCommand command = new SqlCommand(query, db))
{
if (db.State == ConnectionState.Closed)
{
db.Open();
command.Parameters.AddWithValue("#userName", user.UserName);
SqlDataAdapter dataAdapter = new SqlDataAdapter(command);
table = new DataTable();
dataAdapter.Fill(table);
}
}
db.Close();
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
return table;
}
}
This function is in a class library. The function is called in the WPF project, this is the code:
private void BtnDisplay_Click(object sender, RoutedEventArgs e)
{
string userName = CmboxUserN.SelectedItem.ToString();
User user1 = new User
{
UserName = userName
};
DataTable table = data.ReadData(user1);
gridModules.DataContext= table;
}
Try these changes. It seems that the line table = new DataTable(); is never being hit. You don't need to check to make sure the connection is in a closed state because you are using a using statement.
public DataTable ReadData(User user)
{
using (SqlConnection db = new SqlConnection(AppConnect.Connection))
{
string query = "SELECT moduleCode,moduleName,modCredits,modHrsLeft FROM [Module] WHERE userName=#userName";
try
{
using (SqlCommand command = new SqlCommand(query, db))
{
db.Open();
command.Parameters.AddWithValue("#userName", user.UserName);
SqlDataAdapter dataAdapter = new SqlDataAdapter(command);
table = new DataTable();
dataAdapter.Fill(table);
}
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
return table;
}
}
Also, you don't need to .Close() the connection because the SqlConnection is in a using statement, which means the object will be disposed of when the scope of the using statement is exited.
One other tip: You should change the code to have the try catch around everyting and if there are any errors at all, log the errors to console and return a new DataTable().
I have fetched the data from SQL server to datagridview but I don't know how to change the cell value. I have to change the fetched value 1 and 0 to available and unavailable. here is my code for fetching data ... please help.
private void btnsearch_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection("server = 192.168.100.6;Database=sms;UID=sa;Password=1234;");
SqlCommand cmd = new SqlCommand("Select id as 'Book ID',name as 'Name' , status as 'Status' from book where Name = #name", con);
cmd.Parameters.AddWithValue("#name", txtFirstName.Text);
try
{
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
DataTable dt = new DataTable();
da.Fill(dt);
BindingSource bsource = new BindingSource();
bsource.DataSource = dt;
dataGridView1.DataSource = bsource;
}
catch (Exception ec)
{
MessageBox.Show(ec.Message);
}
// chage_value();
dataGridView1.Show();
}
}
Please find below answer
private void btnsearch_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection("server = 192.168.100.6;Database=sms;UID=sa;Password=1234;");
string sSql=#"Select id as 'Book ID',name as 'Name' ,
Case when status=0 then 'unavailable' else 'available '
End as 'Status' from
book where Name ='"+txtFirstName.Text +"'"
SqlCommand cmd = new SqlCommand(sSql, con);
try
{
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
DataTable dt = new DataTable();
da.Fill(dt);
dataGridView1.DataSource = dt;
}
catch (Exception ec)
{
MessageBox.Show(ec.Message);
}
// chage_value();
dataGridView1.Show();
}
}
First of all, try to store your queries in variables. This will help you in the long run. Also, it is good practise to check whether you are connected or not before trying to send a query away to the server. It is important to remeber that when you fetch data from your server, it will most likely be seen as a string, so if you want to compare it as a number, you need to convert it first.
What you could do is something similar to what i've written below. You count the amount of answers your query returns, then loop through them and check whether they are 0 or 1. Then just replace the value with Avaliable or Unavaliable.
if (dbCon.IsConnect()){
MySqlCommand idCmd = new MySqlCommand("Select * from " + da.DataGridView1.Text, dbCon.Connection);
using (MySqlDataReader reader = idCmd.ExecuteReader()){
// List<string> stringArray = new List<string>(); // you could use this string array to compare them, if you like this approach more.
while (reader.Read()){
var checkStatus= reader["Status"].ToString();
Console.WriteLine("Status: " + checkStatus.Split(' ').Count()); //checks how many items you've got.
foreach (var item in checkStatus.Split(' ').Select(x => x.Trim()).Where(x => !string.IsNullOrWhiteSpace(x)).ToArray()){
var item2 = 0.0; // your 0 or 1 for avaliable or unavaliable..
try{
item2 = double.Parse(item.ToString());
if(strcmp(item2,'0') == 1){ //assuming you only have 0's and 1's.
item2 = "unavaliable";
}else{
item2 = "avaliable";
}
}
catch (Exception){
//do what you want
}
Console.WriteLine("item: " + item2);
}
}
dbCon.Close();
}
}
return //what you want;
}
Currently i'm populating a combobox with items from a database.However, i want the first item of combobox to be "---Select---".I am using the following code.All the items from database are getting populated but not the item "---Select---". Any help in this regard is highly appreciated.
private void popClass()
{
cmbClass.Items.Clear();
DataSet ds = new DataSet();
cmbClass.Items.Add("---Select----");
string sqlPS = #"SELECT * FROM tblclass_msb";
try
{
using (FbConnection conPS = new FbConnection(connectionString))
{
conPS.Open();
using (FbCommand cmdPS = new FbCommand(sqlPS, conPS))
{
using (FbDataAdapter da = new FbDataAdapter())
{
da.SelectCommand = cmdPS;
da.Fill(ds);
cmbClass.DataSource = ds.Tables[0];
cmbClass.ValueMember = "c_id";
cmbClass.DisplayMember = "c_name";
}
}
}
}
catch (FbException ex)
{
MessageBox.Show("PC-->>" + ex.Message);
}
}
i have tried other solutions mentioned somewhere in the other threads but its not working for me
you have to add new row at zero position you an do it like this:
private void popClass()
{
cmbClass.Items.Clear();
DataSet ds = new DataSet();
cmbClass.Items.Add("---Select----");
string sqlPS = #"SELECT * FROM tblclass_msb";
try
{
using (FbConnection conPS = new FbConnection(connectionString))
{
conPS.Open();
using (FbCommand cmdPS = new FbCommand(sqlPS, conPS))
{
using (FbDataAdapter da = new FbDataAdapter())
{
da.SelectCommand = cmdPS;
da.Fill(ds);
DataRow dr=ds.Tables[0].NewRow();
dr["c_id"]=0;
dr["c_name"]="--Select--";
ds.Tables[0].Rows.InsertAt( dr,0);
cmbClass.DataSource = ds.Tables[0];
cmbClass.ValueMember = "c_id";
cmbClass.DisplayMember = "c_name";
}
}
}
}
catch (FbException ex)
{
MessageBox.Show("PC-->>" + ex.Message);
}
}
If you were connecting to SQL Server using SqlCommand, you could simply change the SQL statement to the following:
string sqlPS = #"select 0 as c_id, '--Select--' as c_name union SELECT c_id, c_name FROM tblclass_msb";
However, it looks like you're connecting to Firebird and I can't be sure if union is supported.
I can not get any row data from database using c# asp.net.I am trying to fetch one row data from my DB but it is not returning any row.I am using 3-tire architecture for this and i am explaining my code below.
index.aspx.cs:
protected void userLogin_Click(object sender, EventArgs e)
{
if (loginemail.Text.Trim().Length > 0 && loginpass.Text.Trim().Length >= 6)
{
objUserBO.email_id = loginemail.Text.Trim();
objUserBO.password = loginpass.Text.Trim();
DataTable dt= objUserBL.getUserDetails(objUserBO);
Response.Write(dt.Rows.Count);
}
}
userBL.cs:
public DataTable getUserDetails(userBO objUserBO)
{
userDL objUserDL = new userDL();
try
{
DataTable dt = objUserDL.getUserDetails(objUserBO);
return dt;
}
catch (Exception e)
{
throw e;
}
}
userDL.cs:
public DataTable getUserDetails(userBO objUserBO)
{
SqlConnection con = new SqlConnection(CmVar.convar);
try
{
con.Open();
DataTable dt = new DataTable();
string sql = "SELECT * from T_User_Master WHERE User_Email_ID= ' " + objUserBO.email_id + "'";
SqlCommand cmd = new SqlCommand(sql, con);
SqlDataAdapter objadp = new SqlDataAdapter(cmd);
objadp.Fill(dt);
con.Close();
return dt;
}
catch(Exception e)
{
throw e;
}
}
When i am checking the output of Response.Write(dt.Rows.Count);,it is showing 0.So please help me to resolve this issue.
It looks like your your query string has a redundant space between ' and " mark. That might be causing all the trouble as your email gets space in front.
It is by all means better to add parameters to your query with use of SqlConnection.Parameters property.
string sql = "SELECT * from T_User_Master WHERE User_Email_ID=#userID";
SqlCommand cmd = new SqlCommand(sql, con);
cmd.Parameters.Add("#userID", SqlDbType.NVarChar);
cmd.Parameters["#userID"].Value = objUserBO.email_id;
I'm new in C#. I'm trying to query an *.accdb database, but having 0 row in response and datagrid stays clear. Query works from MS Access. What's wrong?
Main form class
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
OleDbConnection database;
public Form1()
{
InitializeComponent();
}
private void filterButton_Click(object sender, EventArgs e)
{
MessageBox.Show(nameFilter.Text);
InitializeComponent();
string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\qwe.accdb;";
try
{
database = new OleDbConnection(connectionString);
database.Open();
string queryString = "SELECT id FROM table1";
loadDataGrid(queryString);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return;
}
}
public void loadDataGrid(string sqlQueryString) {
OleDbCommand comm = new OleDbCommand();
comm.CommandText = sqlQueryString;
comm.CommandType = CommandType.Text;
comm.Connection = database;
Int32 returnValue = comm.ExecuteNonQuery();
MessageBox.Show(returnValue.ToString());
OleDbCommand SQLQuery = new OleDbCommand();
DataTable data = null;
dataGridView1.DataSource = null;
SQLQuery.Connection = null;
OleDbDataAdapter dataAdapter = null;
dataGridView1.Columns.Clear(); // <-- clear columns
SQLQuery.CommandText = sqlQueryString;
SQLQuery.Connection = database;
data = new DataTable();
dataAdapter = new OleDbDataAdapter(SQLQuery);
dataAdapter.Fill(data);
dataGridView1.DataSource = data;
MessageBox.Show(data.ToString());
dataGridView1.AllowUserToAddRows = false; // <-- remove the null line
dataGridView1.ReadOnly = true; // <-- so the user cannot type
}
}
}
Why not something along the lines of:
private void filterButton_Click(object sender, EventArgs e)
{
dataGridView1.Columns.Clear();
MessageBox.Show(nameFilter.Text);
InitializeComponent();
string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\qwe.accdb;";
try
{
using (DataTable dt = new DataTable())
{
using (OleDbDataAdapter da = new OleDbDataAdapter(new SqlCommand("SELECT id FROM table1",new OleDbConnection(connectionString))))
{
da.Fill(dt);
MessageBox.Show(dt.Rows.Count.ToString());
dataGridView1.DataSource = dt;
dataGridView1.Update();
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return;
}
}