How to display data on a new instance of an existing form?

Question

Hi I'm new to c#. I am buil I have a datagrid where that displays a few cells about projects and when the user clicks on a row I want to open a new instance of the projects form and display all the projects info (from a MySQL db). I'm stuck on how to pass the data to the new instance of the projects form. The new instance of the form displays ok but how to reference the original form's text boxes and other objects is the problem I have. Please help! below is the line of code: public void projectGrid_CellContentClick(object sender DataGridViewCellEventArgs e) { //Public String sid; //string sid = projectGrid.Rows[projectGrid.CurrentRow.Index].Cells[ID].Value.ToString(); project f1 = new project(); f1.Show();// How to make this form load with the correct data? } Thanks David

David Ditudidi · Answer

Hi Thanks a mil I followed ur tip and with some more twiking I got it working. Thanks evryone for ur answers! Dave

Sam Hobbs · Answer

I don't have the time at the moment to provide a more thorough reply but the following is what I would do or at least closer to what I would do. There is a managed (.Net) interface to MySQL; you need to use that. I think you can use it to create a data source that includes a query that takes the id as a parameter. I would create a form bound to the data source. Then I would create a member in the form for the id and set that member in Form1 before showing the project form. Then in the project form there will be a function to fill the data source and that function will take the id as a parameter. You could create the project form without writing any code if you know how to use data sources. Yes without writing any code except the two lines I described.

theLizard · Answer

This is the simplest way public void projectGrid_CellContentClick(object sender DataGridViewCellEventArgs e) { //Public String sid; string sid = projectGrid.Rows[projectGrid.CurrentRow.Index].Cells[ID].Value.ToString(); project f1 = new project(); f1.Controls[textBox2].Text = sid; f1.Show();// How to make this form load with the correct data? }

David Ditudidi · Answer

Hi Sam This is the scenario: I have a datagrid in Form1 and it displays some information (e.g. project number name lead and end date) about the projects that I currently have in a MySQL database. What I want to do is when a user double clicks any of the rows of the projects datagridview I want to open a form called project that will display all the information about the selected project. The line below is to make sure that a new form is displayed each time (to cater for multiple users): project f1 = new project(); f1.Show(); So f1 will display the result of a query (select * from projects where id = sid - sid being the value in the cell of the ID column for the selected project). The problem that I have is this: How to display the data (from the query result) in the correct text boxes e.g. textBox1.text = rdr[projectName]; How to get access to textBoxes etc of the project form from f1 - an instance of the project form. Please if you still need more info just let me know. Thanks David

Sam Hobbs · Answer

You still have not made it clear whether they are all the same form or if there are two forms. You also are not making it clear whether you need to do a query of the database to get data for the new form. I assume you do and if so then it helps to make that clear. I also don't understand why you must access the first form's controls instead of going the other direction as I describe. You can do it the way you want to if you want to or need to but if you need to also do a database query then there are alternatives that will be easier.

David Ditudidi · Answer

Hi guys first thanks for the replies. I think I did not give you a clear explanation of what i need. I need to get access to the projects form's controls (e.g. text boxes etc) from f1 in order to display a query result. Basicaly some way to reference projects form's controls. thanks David

Sam Hobbs · Answer

Perhaps I misunderstand what you need to do but I think an even easier way of doing it is to create members in the project class for the data. The members would need to be public of course. Then in the project's Form Load event put the data in the controls and do whatever else you need to the data. Then when the user clicks on a row after creating an instance of the form (such as in project f1 = new project();) and before showing the form (as in f1.Show();) set the members in the new instance to the data from the current instance. I think it is strange that you are using the same form for both purposes and perhaps you are not actuallly doing that; perhaps you just are not explaining what you are actually doing. If however you are using the same form then it might work better to do as I explained above since for the first instance of the form there will not be a previous instance.

Vulpes · Answer

Basically the new instance of the project form needs a reference to the old one. The easiest way to do this would be add a public (or internal) method to the project form which can be passed a reference to the old one. This method can then transfer the values. However to facilitate this you'll need to change the accessibility of the relevant textboxes etc. from private to public (or internal). So you'd have something like this on the project form: public void projectGrid_CellContentClick(object sender DataGridViewCellEventArgs e) { DataGridView dgv = (DataGridView)sender; project proj = (project)dgv.FindForm(); if (proj.Name != project2) { project f1 = new project(); f1.Name = project2; f1.Show(); f1.TransferData(this); } } public void TransferData(project proj) { if (this.Name == project2) { this.textBox1.Text = proj.textBox1.Text; // etc } } You'll notice that I've included a check to ensure that the correct instance is doing the appropriate things.