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Check value of datatable with C#

I want to check if values of datatable of the same column are equals to "int" or not , so if it's true i want to calculate with content value the sum. This is my code which return always when i click on sum button "pas tous entier" .
Thank you in advance!
private void button7_Click(object sender, EventArgs e)
{
int i = 0, s = 0;
String type ="int";
DataTable dt = new DataTable("Table_insertion");
bool exists = dt.AsEnumerable().Any(row => type == row.Field<String>("Type"));
if (exists== true)
{
for (i = 0; i < dataGridView1.Rows.Count; ++i)
{
s += Convert.ToInt32(dataGridView1.Rows[i].Cells[2].Value);
}
label5.Text = s.ToString();
}
else
{
MessageBox.Show("pas tous entiers");
}
}

The datatable seems unnecessary here.
Maybe the following is enough.
for (i = 0; i < dataGridView1.Rows.Count; ++i)
{
var str = dataGridView1.Rows[i].Cells[2].Value?.ToString();
if( !string.IsNullOrEmpty(str) && Int32.TryParse(str, out var parsed)
{
s += parsed;
}
}
If you want to check the type of the column in a datatable you can check its DataType.
foreach (var col in datatable1.Columns)
{
if ( col.DataType == typeof(System.Int16) || col.DataType == typeof(System.Int32)) // Or other types
{
....

Are you just trying to evaluate if the string returned contains only numbers? If so, you may want to use a regex match on the data. There is a great example here: Regex for numbers only

How to check duplicate rows in dataset?

I have a dataset which has duplicate rows i want my error message to execute when duplicate rows are present.
Below is my code please help
DataSet dsXml = new DataSet();
dsXml.ReadXml(new XmlTextReader(new StringReader(xml)));
Hashtable hTable = new Hashtable();
ArrayList duplicateList = new ArrayList();
foreach (DataRow drow in dsXml.Tables[0].Rows)
{
if (hTable.Contains(drow))
{
duplicateList.Add(drow);
}
else
{
script.Append("alert('Error - There are some Duplicate entries.'); ");
ErrorOcc = true;
if (ErrorOcc)
{
this.ScriptOutput = script + " ValidateBeforeSaving = false;";
this.StayContent = "yes";
return;
}
}
}

Your code is not working, because DataRow instances will be compared by references instead of comparing their fields. You can use custom comparer:
public class CustomDataRowComparer : IEqualityComparer<DataRow>
{
public bool Equals(DataRow x, DataRow y)
{
if (x.ItemArray.Length != y.ItemArray.Length)
return false;
for (int i = 0; i < x.ItemArray.Length; i++)
if (!x[i].Equals(y[i]))
return false;
return true;
}
public int GetHashCode(DataRow obj)
{
int hash = 17;
foreach (object field in obj.ItemArray)
hash = hash * 19 + field.GetHashCode();
return hash;
}
}
or use existing DataRowComparer which compares DataRow objects for equivalence by using value-based comparison:
HashSet<DataRow> set = new HashSet<DataRow>(DataRowComparer.Default);
// or: new HashSet<DataRow>(new CustomDataRowComparer());
foreach (DataRow row in dsXml.Tables[0].Rows)
{
if (!set.Add(row))
// duplicate row
}
You can also check if duplicated rows exist with Linq to DataSet query:
var duplicatedRowsExist = dsXml.Tables[0].AsEnumerable()
.GroupBy(r => r, DataRowComparer.Default)
.Any(g => g.Count() > 1);

You have to compare the content of the rows, not the rows themselves. Something like this should do it:
var hasDupes = dsXml.Tables[0].Rows
.AsEnumerable()
.GroupBy(row => new
{
row.Field<string>("Title"),
row.Field<string>("Address"),
row.Field<string>("State"),
row.Field<string>("City"),
row.Field<int>("Status"),
row.Field<int>("CreatedBy"),
row.Field<int>("UpdatedBy")
})
.Where(g => g.Count() > 1)
.Any();
if(hasDupes)
//Show error message

I think you have to alter you logic a little. You don't add the row to the hTable, so there are never duplicates. And I guess you have to show the message in the end, else the list will not be complete yet.
As stated by others, you do need Sergeys answer to get the comparison to work. If you have that covered, this code will solve the other logic problems.
foreach (DataRow drow in dsXml.Tables[0].Rows)
{
if (!hTable.Contains(drow))
{
hTable.Contains(drow);
hTable.Add(drow);
}
else
{
duplicateList.Add(drow);
}
}
script.Append("alert('Error - There are some Duplicate entries.'); ");
ErrorOcc = true;
if (ErrorOcc)
{
this.ScriptOutput = script + " ValidateBeforeSaving = false;";
this.StayContent = "yes";
return;
}

First, you need to define your comparison between rows. It appears when you create your hTable there is nothing in it, so the hTable.Contains call is always going to return false.
As a side note, you can't just compare a DataRow with another DataRow, it will use the default equality comparison (implemented using IEqualityComparer) and effectively boils down to a reference equality check, which none of the rows will be equal to each other.
Somewhere, you can either implement your own IEqualityCompariosn, or simply write a custom method to check the values of each row.

Here is the answer of my above Question
You can Check duplicate rows in dataset.. it is working fine try it.
DataSet dsXml = new DataSet();
dsXml.ReadXml(new XmlTextReader(new StringReader(xml)));
List<string> duplicateList = new List<string>();
foreach (DataRow drow in dsXml.Tables[0].Rows)
{
string strr = "";
for (int j = 0; j < dsXml.Tables[0].Columns.Count; j++ )
{
strr += drow[j];
}
if (!duplicateList.Contains(strr))
{
duplicateList.Add(strr);
}
else
{
script.Append("alert('Error - There are some Duplicate entries.'); ");
ErrorOcc = true;
if (ErrorOcc)
{
this.ScriptOutput = script + " ValidateBeforeSaving = false;";
this.StayContent = "yes";
return;
}
}
}

Delete and remove the row matching string?

I want to search for a string in DataTable if it starts with "null" delete this string, if this row has no values then erase this row too. Can someone show me how to do it?
ID Name Comment
2 lola hallo
5 miky hi
null0 // delete null0 and remove this row
null1 ko // delete null1 but do not remove this row
1 hub why
3 null2 //delete null2 but do not remove this row
I tried to delete "null" but it doesn't work.
My Code:
int ct1 = 0;
for (int i = 0; i < resE1.Rows.Count; i++ )
{
if(resE1.Rows[i]["SignalName"].ToString() == "null" + ct1)
{
resE1.Rows[i].SetField<String>(2, "");
}
ct1++;
}
I find a solution to replace "null*" with empty spaces, but now I want to erase this row if the cells values of this row are empty, how can i do it?
int ct1 = 0;
for (int i = 0; i < resE1.Rows.Count; i++)
{
string fix = resE1.Rows[i]["SignalName"].ToString();
if(fix.Contains("null"))
{
resE1.Rows[i].SetField<String>(2, "");
}
ct1++;
}

I tried this. Works for me.
List<DataRow> rowsToRemove = new List<DataRow>();
foreach (DataRow dr in resE1.Rows)
{
if (dr["Name"].ToString().IndexOf("null") == 0)
{
dr.SetField("Name", "");
}
bool hasValue = false;
for (int i = 0; i < dr.ItemArray.Count(); i++)
{
if (!dr[i].ToString().Equals(String.Empty))
hasValue = true;
}
if (!hasValue) rowsToRemove.Add(dr);
}
foreach(DataRow dr in rowsToRemove)
{
dr.Delete();
}

Here is your code changed so it works although I don't like how it is written. Check the answer:
int ct1 = 0;
int i = 0;
while(i < dt.Rows.Count)
{
if ( dt.Rows[i]["Name"].ToString() == "null" + ct1)
{
if ((dt.Rows[i][0] == null || dt.Rows[i][0].ToString() == string.Empty) && (dt.Rows[i][2] == null || dt.Rows[i][2].ToString() == string.Empty))
{
dt.Rows.RemoveAt(i);
i--;
}
else
{
dt.Rows[i].SetField<String>(1, "");
}
ct1++;
}
i++;
}

Assuming your DataTable has column "Name" of type string you can achieve it like this:
private DataTable RemoveUnwanted(DataTable source)
{
var rowsEnu = source.Rows.GetEnumerator();
while (rowsEnu.MoveNext())
{
((DataRow)rowsEnu.Current)["Name"] = ((DataRow)rowsEnu.Current)["Name"].ToString().StartsWith("null") ? string.Empty : ((DataRow)rowsEnu.Current)["Name"];
}
return (from i in source.AsEnumerable()
where !(i.ItemArray.All(o => string.IsNullOrEmpty(o.ToString())))
select i).CopyToDataTable();
}
You will also need reference to System.Data.DataSetExtensions.

To answer one of your questions, to delete the entire row do something like this:
if(resE1.Rows[i].Contains("null") && (resE1.Rows[i]["ID"].ToString() == "") && (resE1.Rows[i]["Comment"].ToString() == ""))
{
resE1.Rows[i].Delete();
}
bool emptyFlag = false;
if(resE1.Rows[i].Contains("null"))
{
for(int j = 0; j < resE1.Columns.Count; j++)
{
if(resE1.Rows[i][j].Equals(""))
emptyFlag = true;
else
emptyFlag = false;
}
if(emptyFlag)
resE1.Rows[i].Delete();
}

You need something like this:
String test = "Null01";
if (test.IndexOf("Null") == 0)
{
test = test.Replace("Null", String.Empty);
}
For second part of your question, just check if Comments are null or empty then replace the string too.
Arrange code according to your own requirement.

Search string in Listbox

I'm having troubles finding a string into a listbox, my string NombreCompleto is made of 3 strings that I previously had read from a file(ESSD), after I had recovered this string, I want to know if this string is in my listbox3, I tried several methods but it doesnt seem to work.
Here is my code.
foreach (string h in Directory.EnumerateFiles(NomDirec, "resume*"))
{
this.listBox1.Items.Add(h);
var NombreLinea = File.ReadLines(h);
foreach (string item in NombreLinea)
{
NombreAbuscar.Add(item.Remove(item.IndexOf(':')));
this.listBox3.Items.Add(item.Remove(item.IndexOf(':')));
}
foreach (string t in Directory.EnumerateFiles(NomDirec, "ESSD1*"))
{
string[] Nombre = File.ReadLines(t).ElementAtOrDefault(6).Split(':');
string[] ApellidoPat = File.ReadLines(t).ElementAtOrDefault(7).Split(':');
string[] ApellidoMat = File.ReadLines(t).ElementAtOrDefault(8).Split(':');
string NombreCompleto = ApellidoPat[1]+" "+ ApellidoMat[1] +","+" "+ Nombre[1];
string Nom2 = NombreCompleto.ToString();
int index = listBox3.FindString(Nom2);
if (index != -1)
{
this.listBox1.Items.Add(t);
MessageBox.Show("Find It");
}
else { MessageBox.Show("Not Found :#"); }
}

You can try with this code - based on Linq operator Where, ...
var selectedItems = from li in listBox3.Items
where li.Text == Nom2
select li.Text;
if(selectedItems.Any())
....

Try this out:
int index = -1;
for (int i = 0; i < listBox3.Items.Count; ++i)
if (listBox3.Items[i].Text == Nom2) { index = i; break; }
if (index != -1)
{
this.listBox1.Items.Add(t);
MessageBox.Show("Find It");
}
else { MessageBox.Show("Not Found :#");

Really easy way to find if a certain string is in a listbox.
private void btnAddRecipe_Click(object sender, EventArgs e)
{
bool DoesItemExist = false;
string searchString = txtRecipeName.Text;
int index = lstRecipes.FindStringExact(searchString, -1);
if (index != -1) DoesItemExist = true;
else DoesItemExist = false;
if (DoesItemExist)
{
//do something
}
else
{
MessageBox.Show("Not found", "Message", MessageBoxButtons.RetryCancel, MessageBoxIcon.Stop);
}
PopulateRecipe();
}

Find a row in dataGridView based on column and value

I have a dataGridView that has 3 columns: SystemId, FirstName, LastName that is bound using database information. I would like to highlight a certain row, which I would do using:
dataGridView1.Rows[????].Selected = true;
The row ID I however do not know and the bindingsource keeps changing, thus row 10 could be "John Smith" in one instance but not even exist in another (I have a filter that filters out the source based on what user enters, so typing in "joh" would yield all rows where first / last name have "joh" in them, thus my list can go from 50 names to 3 in a click).
I want to find a way how I can select a row based on SystemId and a corresponding number. I can get the system ID using the following method:
systemId = dataGridView1.Rows[dataGridView1.CurrentRow.Index].Cells["SystemId"].Value.ToString();
Now I just need to apply it to the row selector. Something like dataGridView1.Columns["SystemId"].IndexOf(systemId} but that does not work (nor does such method exist). Any help is greatly appreciated.

This will give you the gridview row index for the value:
String searchValue = "somestring";
int rowIndex = -1;
foreach(DataGridViewRow row in DataGridView1.Rows)
{
if(row.Cells[1].Value.ToString().Equals(searchValue))
{
rowIndex = row.Index;
break;
}
}
Or a LINQ query
int rowIndex = -1;
DataGridViewRow row = dgv.Rows
.Cast<DataGridViewRow>()
.Where(r => r.Cells["SystemId"].Value.ToString().Equals(searchValue))
.First();
rowIndex = row.Index;
then you can do:
dataGridView1.Rows[rowIndex].Selected = true;

The above answers only work if AllowUserToAddRows is set to false. If that property is set to true, then you will get a NullReferenceException when the loop or Linq query tries to negotiate the new row. I've modified the two accepted answers above to handle AllowUserToAddRows = true.
Loop answer:
String searchValue = "somestring";
int rowIndex = -1;
foreach(DataGridViewRow row in DataGridView1.Rows)
{
if (row.Cells["SystemId"].Value != null) // Need to check for null if new row is exposed
{
if(row.Cells["SystemId"].Value.ToString().Equals(searchValue))
{
rowIndex = row.Index;
break;
}
}
}
LINQ answer:
int rowIndex = -1;
bool tempAllowUserToAddRows = dgv.AllowUserToAddRows;
dgv.AllowUserToAddRows = false; // Turn off or .Value below will throw null exception
DataGridViewRow row = dgv.Rows
.Cast<DataGridViewRow>()
.Where(r => r.Cells["SystemId"].Value.ToString().Equals(searchValue))
.First();
rowIndex = row.Index;
dgv.AllowUserToAddRows = tempAllowUserToAddRows;

Or you can use like this. This may be faster.
int iFindNo = 14;
int j = dataGridView1.Rows.Count-1;
int iRowIndex = -1;
for (int i = 0; i < Convert.ToInt32(dataGridView1.Rows.Count/2) +1; i++)
{
if (Convert.ToInt32(dataGridView1.Rows[i].Cells[0].Value) == iFindNo)
{
iRowIndex = i;
break;
}
if (Convert.ToInt32(dataGridView1.Rows[j].Cells[0].Value) == iFindNo)
{
iRowIndex = j;
break;
}
j--;
}
if (iRowIndex != -1)
MessageBox.Show("Index is " + iRowIndex.ToString());
else
MessageBox.Show("Index not found." );

Try this:
string searchValue = textBox3.Text;
int rowIndex = -1;
dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
try
{
foreach (DataGridViewRow row in dataGridView1.Rows)
{
if (row.Cells["peseneli"].Value.ToString().Equals(searchValue))
{
rowIndex = row.Index;
dataGridView1.CurrentCell = dataGridView1.Rows[rowIndex].Cells[0];
dataGridView1.Rows[dataGridView1.CurrentCell.RowIndex].Selected = true;
break;
}
}
}
catch (Exception exc)
{
MessageBox.Show(exc.Message);
}

If you just want to check if that item exists:
IEnumerable<DataGridViewRow> rows = grdPdfs.Rows
.Cast<DataGridViewRow>()
.Where(r => r.Cells["SystemId"].Value.ToString().Equals(searchValue));
if (rows.Count() == 0)
{
// Not Found
}
else
{
// Found
}

This builds on the above answer from Gordon--not all of it is my original work.
What I did was add a more generic method to my static utility class.
public static int MatchingRowIndex(DataGridView dgv, string columnName, string searchValue)
{
int rowIndex = -1;
bool tempAllowUserToAddRows = dgv.AllowUserToAddRows;
dgv.AllowUserToAddRows = false; // Turn off or .Value below will throw null exception
if (dgv.Rows.Count > 0 && dgv.Columns.Count > 0 && dgv.Columns[columnName] != null)
{
DataGridViewRow row = dgv.Rows
.Cast<DataGridViewRow>()
.FirstOrDefault(r => r.Cells[columnName].Value.ToString().Equals(searchValue));
rowIndex = row.Index;
}
dgv.AllowUserToAddRows = tempAllowUserToAddRows;
return rowIndex;
}
Then in whatever form I want to use it, I call the method passing the DataGridView, column name and search value. For simplicity I am converting everything to strings for the search, though it would be easy enough to add overloads for specifying the data types.
private void UndeleteSectionInGrid(string sectionLetter)
{
int sectionRowIndex = UtilityMethods.MatchingRowIndex(dgvSections, "SectionLetter", sectionLetter);
dgvSections.Rows[sectionRowIndex].Cells["DeleteSection"].Value = false;
}

Those who use WPF
for (int i = 0; i < dataGridName.Items.Count; i++)
{
string cellValue= ((DataRowView)dataGridName.Items[i]).Row["columnName"].ToString();
if (cellValue.Equals("Search_string")) // check the search_string is present in the row of ColumnName
{
object item = dataGridName.Items[i];
dataGridName.SelectedItem = item; // selecting the row of dataGridName
dataGridName.ScrollIntoView(item);
break;
}
}
if you want to get the selected row items after this, the follwing code snippet is helpful
DataRowView drv = dataGridName.SelectedItem as DataRowView;
DataRow dr = drv.Row;
string item1= Convert.ToString(dr.ItemArray[0]);// get the first column value from selected row
string item2= Convert.ToString(dr.ItemArray[1]);// get the second column value from selected row

string text = "param";
var rows = dataGridViewlist.Rows.OfType<DataGridViewRow>()
.Select(x => new { Value = x.Cells[6].Value.ToString(), Index = x.Index }).ToList();
var index= rows.Where(w => w.Value == text).Select(s => s.Index).FirstOrDefault();

You can try:
string DT = string.Empty;
try
{
DT = $"{dataGridView1.SelectedRows[0].Cells[1].Value}-{dataGridView1.SelectedRows[0].Cells[2].Value}-{dataGridView1.SelectedRows[0].Cells[3].Value}-{dataGridView1.SelectedRows[0].Cells[4].Value}";
}
catch { }
try
{
dataGridView1.Rows.Cast<DataGridViewRow>().Where(x => $"{x.Cells[1].Value}-{x.Cells[2].Value}-{x.Cells[3].Value}-{x.Cells[4].Value}" == DT).ToList()[0].Selected = true;
}
catch (Exception ex) { }