Datagridview.datasource = datatable;

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In my code every thing is good...When I am executing this statement it showing the error

Object reference not set to an instance of an object.

and showing an exception NullReferenceException....

please help me...
Thanks in advance....

Posted 9-Jan-13 0:22am

Bharath Kumar Gorle

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prashant patil 4987 9-Jan-13 7:25am

post your code

2 solutions

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pranathis012 · Answer 1 · 2013-01-09T00:25:00

Solution 1

Hi,

whatever you assigned the DataTable that datatable having no data.
Please put a break point and check your datatable having data or not.

Posted 9-Jan-13 0:25am

pranathis012

Comments

Bharath Kumar Gorle 9-Jan-13 6:27am

if (dt.Rows.Count > 0)
dataGridView1.DataSource = dt;

i used this code..even i get thet error...

Yugal Pandya 9-Jan-13 7:24am

try This

if (dt!=null)
{
if(dt.rows.count>0)
{
dataGridView1.DataSource = null;
dataGridView1.DataSource = dt;
}
}

Bharath Kumar Gorle 9-Jan-13 7:30am

Even though it is showing the same error....

[no name] 9-Jan-13 6:40am

please send me your code

Bharath Kumar Gorle 9-Jan-13 7:37am

form1
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;
using System.Windows.Forms;
using DevComponents.DotNetBar;
using System.Data.SqlClient;
using System.Configuration;
using System.IO;

namespace Employee_Management
{
public partial class ViewDetails : DevComponents.DotNetBar.Metro.MetroForm
{

byte[] byteImg;
public ViewDetails()
{
InitializeComponent();
}

DataSet ds = new DataSet();

private void Form7_Load(object sender, EventArgs e)
{
// TODO: This line of code loads data into the 'emp_mgmtDataSet1.employee' table. You can move, or remove it, as needed.
this.employeeTableAdapter1.Fill(this.emp_mgmtDataSet1.employee);

// TODO: This line of code loads data into the 'emp_mgmtDataSet.employee' table. You can move, or remove it, as needed.
this.employeeTableAdapter.Fill(this.emp_mgmtDataSet.employee);
foreach (var ctrl in this.Controls)
if (ctrl is TextBox)
(ctrl as TextBox).ReadOnly = true;
}

#region Button_Click_Events
private void button1_Click(object sender, EventArgs e)
{
button3.Visible = true;
textBox14.Visible = true;
foreach (var ctrl in this.Controls)
{
if (ctrl is TextBox)
(ctrl as TextBox).ReadOnly = false;
}

}

private void button2_Click(object sender, EventArgs e)
{
string str = "update employee set fname ='" + textBox1.Text + "',lname ='" + textBox2.Text + "' ,email = '" + textBox4.Text + "',mobile = '" + textBox5.Text + "',college ='" + textBox6.Text + "',collegelocation ='" + textBox7.Text + "',fathername ='" + textBox8.Text + "',nationality='" + textBox9.Text + "',dob='" + textBox10.Text + "',gender ='" + textBox11.Text + "',currentaddress = '" + textBox12.Text + "',permanentaddress ='" + textBox13.Text + "',photo= @photo,experience ='" + textBox15.Text + "',currentindustry='" + textBox16.Text + "',domain = '" + textBox17.Text + "',keyskills ='" + textBox18.Text + "' where refid = '" + comboBox1.SelectedValue +"'";
SqlConnection con = new SqlConnection("Data Source=NAROLIS-1-PC;Initial Catalog=emp_mgmt;Persist Security Info=True;User ID=sa;Password=Narolis");
SqlCommand cmd = new SqlCommand(str, con);
byte[] byteImg;

if (pictureBox1.Image != null)
{
MemoryStream ms = new MemoryStream();
pictureBox1.Image.Save(ms, ImageFormat.Jpeg);
byteImg = new byte[ms.Length];
ms.Position = 0;
ms.Read(byteImg, 0, byteImg.Length);
cmd.Parameters.AddWithValue("@photo", byteImg);
}

con.Open();
int n = cmd.ExecuteNonQuery();
con.Close();

if (n > 0)
{
MessageBox.Show("The employee " + comboBox1.SelectedValue + "Hasbeen Modified");
}
else
MessageBox.Show("Upadation failed");

txtclear();
}

private void button3_Click(object sender, EventArgs e)
{
OpenFileDialog open = new OpenFileDialog();
open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp)|*.jpg; *.jpeg; *.gif; *.bmp";
if (open.ShowDialog() == DialogResult.OK)
{
pictureBox1.Image = new Bitmap(open.FileName);
textBox14.Text = open.FileName;
}
}

private void button4_Click(object sender, EventArgs e)
{
string str = comboBox1.SelectedValue.ToString();
//Form6 f6 = n

Bharath Kumar Gorle 9-Jan-13 7:37am

form2

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using DevComponents.DotNetBar;
using DevComponents.DotNetBar.Controls;
using DevComponents.DotNetBar.Rendering;

namespace Employee_Management
{
public partial class Form6 : Office2007Form

{
string combovalue;

private void Form6_Load(object sender, EventArgs e)
{

}

public Form6()
{
InitializeComponent();
}

public Form6(string str1)
{
this.combovalue = str1;
}

ViewDetails f7 = new ViewDetails();
private void GetDa()
{
//f7.fors
}
static SqlConnection con = new SqlConnection("Data Source=NAROLIS-1-PC;Initial Catalog=emp_mgmt;Persist Security Info=True;User ID=sa;Password=Narolis");
static SqlDataAdapter da = new SqlDataAdapter("select * from salary2", con);

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox1.SelectedIndex >= 0)
{
if (comboBox1.SelectedIndex == 0)
{
styleManager1.ManagerStyle = eStyle.Office2007Blue;
RibbonPredefinedColorSchemes.ChangeOffice2007ColorTable(eOffice2007ColorScheme.Blue);
}
else if (comboBox1.SelectedIndex == 1)
{
styleManager1.ManagerStyle = eStyle.Office2007Silver;
RibbonPredefinedColorSchemes.ChangeOffice2007ColorTable(eOffice2007ColorScheme.Silver);
}
else if (comboBox1.SelectedIndex == 2)
{
styleManager1.ManagerStyle = eStyle.Office2007Black;
RibbonPredefinedColorSchemes.ChangeOffice2007ColorTable(eOffice2007ColorScheme.Black);
}
else
{
styleManager1.ManagerStyle = eStyle.Office2007VistaGlass;
RibbonPredefinedColorSchemes.ChangeOffice2007ColorTable(eOffice2007ColorScheme.VistaGlass);
}
}
}

#region UserMethods
#region DataBasesInGrid

public void sal(string refid)
{

string str = "select * from salary2 where refid = '" + refid + "'";
SqlConnection con = new SqlConnection("Data Source=NAROLIS-1-PC;Initial Catalog=emp_mgmt;Persist Security Info=True;User ID=sa;Password=Narolis");
SqlDataAdapter da = new SqlDataAdapter(str, con);
DataTable dt = new DataTable();
dt.Clear();
da.Fill(dt);
if (dt.Rows.Count > 0)
dataGridView1.DataSource = dt;
else
MessageBox.Show("Database is not pakka....");

//DataTable dt = GetDt(str);
//VerticalGrid(dt);
//return dt;
}

public void Perform(string refid)
{
string str = "select * from performance where refid = '" + refid + "'";
DataTable dt = GetDt(str);
dataGridView1.DataSource = dt;
//VerticalGrid(dt);
}

public void Daily(string refid)
{
string str = "select * from dailywork where refid = '" + refid + "'";
DataTable dt = GetDt(str);
VerticalGrid(dt);
}
#endregion

#region Grid

private void VerticalGrid(DataTable dt)
{
// Creating a table for to display in a Vertical manner
DataTable table = new DataTable();

//Get the Number of rows to make new column
for (int i = 0; i <= dt.Rows.Count; i++)
table.Columns.Add(Con
Rep

Bharath Kumar Gorle 9-Jan-13 7:13am

If you have any doubts ask me... i wil tell...

Salman622 15-Sep-14 6:58am

paste your GetDt() function

faranakm123 15-Sep-14 6:02am

Please help me!!!
I have this problem too.what must I do when I assign the datatable with no data to a datasource of datagridview in c#???

Bharath Kumar Gorle · Answer 2 · 2013-01-09T00:30:00

C#

private void button5_Click(object sender, EventArgs e)
        {
           string str = comboBox1.SelectedValue.ToString();            
            Form6 f6 = new Form6();
            f6.Perform(str);
            f6.Show();           
        }

When i Used this Code it is not having any error....

C#

private void button5_Click(object sender, EventArgs e)
        {
           string str = comboBox1.SelectedValue.ToString();
            Form6 f6 = new Form6(str);
            f6.Perform(str);
            f6.Show();
        }
</pre>

When i used this code it showing the error....
here perform() display a daatabase in form6