ComboBox Data Binding

Posted by Anilkumar431 under ADO.NET on 9/26/2015 | Points: 10 | Views : 1005 | Status : [Member] | Replies : 2

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Hi All,

I am doing a project in Windows forms application with the hellp of C# prog Lang. I got a small confusion when i am binding the data to ComboBox from Database.

Ex:
Image Id column is DisplayMember of ComboBox and the values like this 1 11 12 15 18 19 21.

But i need to display the ImageId's in the ComboBox as 1 2 3 4 5 6 etc....
Please any one help me out from this situation.

Thanks in Advance.

Anilkumar Madishetty

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Posted by: Rajnilari2015 on: 9/26/2015 [Member] [Microsoft_MVP] [MVP] Platinum | Points: 25

2	I presume you have the below initial setup DataTable dt = GetData(); // Implement the function to retrieve data. comboBox1.Datasource = dt; //set the combobox data source comboBox1.DisplayMember = ImageID; // Display column comboBox1.ValueMember = ImageData; // Value member column And here is a simulated version of GetData() public DataTable GetData() { DataTable dt = new DataTable(); //Add some columns dt.Columns.Add(new DataColumn("ImageID", typeof(Int32))); dt.Columns.Add(new DataColumn("ImageData", typeof(string))); //Add some rows //First Row DataRow row1 = dt.NewRow(); row1("ImageID") = 1; row1("ImageData") = "ImageData1"; //Second Row DataRow row2 = dt.NewRow(); row2("ImageID") = 11; row2("ImageData") = "ImageData11"; //Third Row DataRow row3 = dt.NewRow(); row3("ImageID") = 12; row3("ImageData") = "ImageData12"; //Fourth Row DataRow row4 = dt.NewRow(); row4("ImageID") = 15; row4("ImageData") = "ImageData15"; //Fifth Row DataRow row5 = dt.NewRow(); row5("ImageID") = 18; row5("ImageData") = "ImageData18"; //Sixth Row DataRow row6 = dt.NewRow(); row6("ImageID") = 19; row6("ImageData") = "ImageData19"; //Seventh Row DataRow row7 = dt.NewRow(); row7("ImageID") = 21; row7("ImageData") = "ImageData21"; //Add the rows to the table dt.Rows.Add(row1); dt.Rows.Add(row2); dt.Rows.Add(row3); dt.Rows.Add(row4); dt.Rows.Add(row5); dt.Rows.Add(row6); dt.Rows.Add(row7); //return the table return dt; } Now you have a new requirement so that the ImageID should be in sequential order. Right? If so, here is an attempt. *Add a new column* to the existing datatable as under** public DataTable GetModifiedTable(DataTable sourceDT) { DataTable destinationDT = sourceDT; DataColumn newCol = new DataColumn("ModifiedImageID", typeof(Int32)); destinationDT.Columns.Add(newCol); int counter = 1; foreach (DataRow row in destinationDT.Rows) { row["ModifiedImageID"] = counter; counter++; } return destinationDT; } And change the below comboBox1.DisplayMember = ModifiedImageID; So the final modified version should be DataTable dt = GetModifiedTable(GetData()); // Implement the function to retrieve data. comboBox1.Datasource = dt; //set the combobox data source comboBox1.DisplayMember = ModifiedImageID; // Display column comboBox1.ValueMember = ImageData; // Value member column Hope this helps. -- Thanks & Regards, RNA Team Anilkumar431, if this helps please login to Mark As Answer. \| Alert Moderator

I presume you have the below initial setup

DataTable dt = GetData(); // Implement the function to retrieve data.

comboBox1.Datasource = dt; //set the combobox data source

comboBox1.DisplayMember = ImageID; // Display column

comboBox1.ValueMember = ImageData;  // Value member column

And here is a simulated version of GetData()

public DataTable GetData()

{

	DataTable dt = new DataTable();



	//Add some columns

	dt.Columns.Add(new DataColumn("ImageID", typeof(Int32)));

	dt.Columns.Add(new DataColumn("ImageData", typeof(string)));



	//Add some rows



	//First Row

	DataRow row1 = dt.NewRow();

	row1("ImageID") = 1;

	row1("ImageData") = "ImageData1";



	//Second Row

	DataRow row2 = dt.NewRow();

	row2("ImageID") = 11;

	row2("ImageData") = "ImageData11";



	//Third Row

	DataRow row3 = dt.NewRow();

	row3("ImageID") = 12;

	row3("ImageData") = "ImageData12";



	//Fourth Row

	DataRow row4 = dt.NewRow();

	row4("ImageID") = 15;

	row4("ImageData") = "ImageData15";



	//Fifth Row

	DataRow row5 = dt.NewRow();

	row5("ImageID") = 18;

	row5("ImageData") = "ImageData18";



	//Sixth Row

	DataRow row6 = dt.NewRow();

	row6("ImageID") = 19;

	row6("ImageData") = "ImageData19";



	//Seventh Row

	DataRow row7 = dt.NewRow();

	row7("ImageID") = 21;

	row7("ImageData") = "ImageData21";



	//Add the rows to the table

	dt.Rows.Add(row1);

	dt.Rows.Add(row2);

	dt.Rows.Add(row3);

	dt.Rows.Add(row4);

	dt.Rows.Add(row5);

	dt.Rows.Add(row6);

	dt.Rows.Add(row7);



	//return the table

	return dt;

}

Now you have a new requirement so that the ImageID should be in sequential order. Right? If so, here is an attempt.
Add a new column to the existing datatable as under

public DataTable GetModifiedTable(DataTable sourceDT)

{

	DataTable destinationDT = sourceDT;

	DataColumn newCol = new DataColumn("ModifiedImageID", typeof(Int32));

	destinationDT.Columns.Add(newCol);

	int counter = 1;

	foreach (DataRow row in destinationDT.Rows) 

	{

    	   row["ModifiedImageID"] = counter;

           counter++;

	}

	return destinationDT;

}

And change the below

comboBox1.DisplayMember = ModifiedImageID;

So the final modified version should be

DataTable dt = GetModifiedTable(GetData()); // Implement the function to retrieve data.

comboBox1.Datasource = dt; //set the combobox data source

comboBox1.DisplayMember = ModifiedImageID; // Display column

comboBox1.ValueMember = ImageData;  // Value member column

Hope this helps.

--
Thanks & Regards,
RNA Team

Anilkumar431, if this helps please login to Mark As Answer. | Alert Moderator

Posted by: Rajnilari2015 on: 9/27/2015 [Member] [Microsoft_MVP] [MVP] Platinum | Points: 25

1	Another way var dt = GetData(); BindingSource bs = new BindingSource(); var lstDS = dt .AsEnumerable() .Select(dr=> ModifiedImageID = Enumerable.Range(1,dt.Rows.Count) ,ImageData = dr.Field<string>("ImageData")) .ToList(); bs.DataSource = lstDS; comboBox1.DataSource = bs.DataSource; comboBox1.DisplayMember = "ModifiedImageID"; comboBox1.ValueMember = "ImageData"; -- Thanks & Regards, RNA Team Anilkumar431, if this helps please login to Mark As Answer. \| Alert Moderator

Another way

var dt = GetData();

BindingSource bs = new BindingSource(); 

var lstDS = dt

                   .AsEnumerable()

                   .Select(dr=> 

                                 ModifiedImageID = Enumerable.Range(1,dt.Rows.Count)

                                 ,ImageData = dr.Field<string>("ImageData"))

                   .ToList();

bs.DataSource = lstDS;

comboBox1.DataSource = bs.DataSource;

comboBox1.DisplayMember = "ModifiedImageID";

comboBox1.ValueMember = "ImageData";

--
Thanks & Regards,
RNA Team

Anilkumar431, if this helps please login to Mark As Answer. | Alert Moderator

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