how to get gridview selected row value to text box which is in another windows form

Well, your question is not very clear for me.
You didn't specify the relationship between your forms (Are they Parent-Child or Siblings?).
And you also didn't specify, what kind of error you get (Compilation error, Exception, etc.).
At this moment the best I can do is to redirect you to this[^] excellent CodeProject article about passing values between forms. I hope it will be useful for you. :)

Try this way please :


1. in grid view cell double click call the form in which u have the text boxes .

2. Pass the values of the data grid view through the forms object to the other forms constructor .

3. Assign the values to the local variables which you fetched through constructor .

4. assign the local variables to the respective text boxes.


----------

if(e.rowIndex>=0 && gridview.RowIndex>0)
{

 Collection_Object SelectedRow = gridview.Rows[e.RowIndex].DataBoundItem as Collection_Object;

Form2 ret = new Form2(this, SelectedRow);
                ret.ShowDialog();

}

this will pass the grid view information to the next form , then you have to receive the values on the form2's constructor then assign to the controls as u desire ..

form1.text1.Text = DataGridView1.item(0,0)Value.ToString() try this one

txtRegID.Text = dt.Rows[0]["RegistrationID"].ToString();

On Form2 Take 4 Public Variable having Appropriate data Type

Let Say

public string Name;
public strint SurName;
 Public int CodeNo;
Public string  City;

public void FillControlsWith_Data()
{

                DataGridViewRow row = new DataGridViewRow();
                row = dataGridView1.CurrentRow;
                intRow = row.Index;
                Name = dataGridView1[0, row.Index].Value.ToString();
                surName= dataGridView1[1, row.Index].Value.ToString();
                CodeNo=int.parse( dataGridView1[2, row.Index].Value.ToString());
                City= dataGridView1[3, row.Index].Value.ToString();

}

On Form 1

Create An Object of form2 Because by Creating object
of from 2 we can access its public propertie by . operator

Form2 ObjFrm2=new Form2();
TextBox1.Text=ObjFrm2.Name.tostring();
TextBox2.Text=ObjFrm2.SurName.tostring();
TextBox3.Text=ObjFrm2.Codeno..tostring();
TextBox4.Text=ObjFrm2.City.tostring();

Hope It Will Help You..:)

If you are using a LINK BUTTON in your grid view, you can use the following code in the ROWCOMMAND method... This code with retrieve all the values in the particular selected row.

// to get the value of the link use the command argument 
FaultId = Convert.ToInt32(e.CommandArgument);

// to get the other column values 
UserId = Convert.ToInt32(((GridViewRow(((LinkButton)e.CommandSource).NamingContainer)).Cells[1].Text);  

Department = ((GridViewRow(((LinkButton)e.CommandSource).NamingContainer)).Cells[2].Text;

ProblemType = ((GridViewRow)(((LinkButton)e.CommandSource).NamingContainer)).Cells[3].Text;

create a session variables for all these collected information in the same page. Use them in the next page... Assign those values to the corresponding text boxes in it

PAGE 1 (SESSION VARIABLE CREATION)

Session["userId"] = UserId;
Session["dept"]=Department;

PAGE 2: (using the session variable)

txtUserId.Text = Convert.ToInt32(Session["UserId"]);
txtDept.Text =  Session["Department"].ToString();

Similar way you can do it for all variables fetched from the seleted row.

[edit]code block added[/edit]

Try This...

textbox1.text=Gridview.CurrentRow.Cells[1].Value.ToString();