?
Solved

How to add an empty col to a grid?

Posted on 2005-03-31
1
Medium Priority
?
355 Views
Last Modified: 2010-04-24
Hi there!

How can i add an empty column to a grid where the data source is an array?

when i get the grid style only the columns with a corresponding mapping name will get displayed in the grid.

So if i don't supply a mapping  name for the empty col when setting the grid style it dosn't display e.g.

Dim gs As System.Windows.Forms.DataGridTableStyle = New DataGridTableStyle
            'Column 1
            Dim colName As DataGridTextBoxColumn = New DataGridTextBoxColumn
            With colName
                .HeaderText = ""
                .Width = 150
                '.MappingName = "DataTypeName"
            End With
            gs.GridColumnStyles.Add(colName )

but because the col does not map to a col in my datasource it won't be displayed.
so what is the way around this, without having an empty col in my array and mapping to that?
0
Comment
Question by:allff
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 14

Accepted Solution

by:
amyhxu earned 400 total points
ID: 13674824
Adding an empty col to the datasource is an easier way. I would suggest you use this way if there's no specific reason not to do this.

But there is a workaround at http://www.syncfusion.com/FAQ/WinForms/   DataGrid section: Q 5.32
I'll just copy it's content here which is written in C#:

The idea is to create the 'bound' table in your dataset, and then add an extra 'unbound' column. The steps are to derive a custom columnstyle that overrides Paint where you calculate and draw the unbound value. You can also override Edit to prevent the user from selecting your unbound column. Then to get your datagrid to use this special column style, you create a tablestyle and add the column styles to it in the order you want the columns to appear in the datagrid. Here are code snippets that derive the column and use the derived column.
 

 
     // custom column style that is an unbound column
 
     public class DataGridUnboundColumn : DataGridTextBoxColumn
 
     {
 
          protected override void Edit(System.Windows.Forms.CurrencyManager source, int rowNum, System.Drawing.Rectangle bounds, bool readOnly, string instantText, bool cellIsVisible)
 
          {
 
               //do not allow the unbound cell to become active
 
               if(this.MappingName == "UnBound")
 
                    return;
 

 
               base.Edit(source, rowNum, bounds, readOnly, instantText, cellIsVisible);
 
          }
 

 
          protected override void Paint(System.Drawing.Graphics g, System.Drawing.Rectangle bounds, System.Windows.Forms.CurrencyManager source, int rowNum, System.Drawing.Brush backBrush, System.Drawing.Brush foreBrush, bool alignToRight)
 
          {
 
           
 
               //clear the cell
 
               g.FillRectangle(new SolidBrush(Color.White), bounds);
 

 
               //compute & draw the value
 
               //string s = string.Format("{0} row", rowNum);
 
               // col 0 + 2 chars from col 1
 
               DataGrid parent = this.DataGridTableStyle.DataGrid;
 
               string s = parent[rowNum, 0].ToString() + ((parent[rowNum, 1].ToString())+ " ").Substring(0,2);
 
               Font font = new Font("Arial", 8.25f);
 
               g.DrawString(s, font, new SolidBrush(Color.Black), bounds.X, bounds.Y);
 
               font.Dispose();
 
               
 
          }
 
     }
 

 
     
 
     //code that uses this unbound column
 
     private void Form1_Load(object sender, System.EventArgs e)
 
     {
 
          // Set the connection and sql strings
 
          // assumes your mdb file is in your root
 
          string connString = @"Provider=Microsoft.JET.OLEDB.4.0;data source=C:\northwind.mdb";
 
          string sqlString = "SELECT * FROM customers";
 

 
          OleDbDataAdapter dataAdapter = null;
 
          DataSet _dataSet = null;
 

 
          try
 
          {
 
               // Connection object
 
               OleDbConnection connection = new OleDbConnection(connString);
 

 
               // Create data adapter object
 
               dataAdapter = new OleDbDataAdapter(sqlString, connection);
 
               
 
               // Create a dataset object and fill with data using data adapter's Fill method
 
               _dataSet = new DataSet();
 
               dataAdapter.Fill(_dataSet, "customers");
 
               connection.Close();
 
          }
 
          catch(Exception ex)
 
          {      
 
               MessageBox.Show("Problem with DB access-\n\n connection: " 
 
                    + connString + "\r\n\r\n query: " + sqlString
 
                    + "\r\n\r\n\r\n" + ex.ToString());
 
               this.Close();
 
               return;
 
          }
 

 
          // Create a table style that will hold the new column style
 
          // that we set and also tie it to our customer's table from our DB
 
          DataGridTableStyle tableStyle = new DataGridTableStyle();
 
          tableStyle.MappingName = "customers";
 

 
          // since the dataset has things like field name and number of columns,
 
          // we will use those to create new columnstyles for the columns in our DB table
 
          int numCols = _dataSet.Tables["customers"].Columns.Count;
 

 
          //add an extra column at the end of our customers table
 
          _dataSet.Tables["customers"].Columns.Add("Unbound");
 

 
          DataGridTextBoxColumn aColumnTextColumn ;
 
          for(int i = 0; i < numCols; ++i)
 
          {
 
               aColumnTextColumn = new DataGridTextBoxColumn();
 
               aColumnTextColumn.HeaderText = _dataSet.Tables["customers"].Columns[i].ColumnName;
 

 
               aColumnTextColumn.MappingName = _dataSet.Tables["customers"].Columns[i].ColumnName;
 
               tableStyle.GridColumnStyles.Add(aColumnTextColumn);
 

 
               //display the extra column after column 1.
 
               if( i == 1)
 
               {
 
                    DataGridUnboundColumn unboundColStyle = new DataGridUnboundColumn();
 
                    unboundColStyle.HeaderText = "UnBound";
 
                    unboundColStyle.MappingName = "UnBound";
 
                    tableStyle.GridColumnStyles.Add(unboundColStyle);                    }
 
               }
 
               
 
               // make the dataGrid use our new tablestyle and bind it to our table
 
               dataGrid1.TableStyles.Clear();
 
               dataGrid1.TableStyles.Add(tableStyle);
 
               dataGrid1.DataSource = _dataSet.Tables["customers"];
 

 
          }
 
     }
 

 
0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Ready to improve network connectivity? Watch this webinar to learn how SD-WANs and a one-click instant connect tool can boost provisions, deployment, and management of your cloud connection.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction As chip makers focus on adding processor cores over increasing clock speed, developers need to utilize the features of modern CPUs.  One of the ways we can do this is by implementing parallel algorithms in our software.   One recent…
Calculating holidays and working days is a function that is often needed yet it is not one found within the Framework. This article presents one approach to building a working-day calculator for use in .NET.
In this video, Percona Director of Solution Engineering Jon Tobin discusses the function and features of Percona Server for MongoDB. How Percona can help Percona can help you determine if Percona Server for MongoDB is the right solution for …
How to fix incompatible JVM issue while installing Eclipse While installing Eclipse in windows, got one error like above and unable to proceed with the installation. This video describes how to successfully install Eclipse. How to solve incompa…
Suggested Courses
Course of the Month10 days, 11 hours left to enroll

765 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question