How to set width of mat-table column in angular?

Question

using css we can adjust specific column width which i put in below code.

user.component.css

table{
 width: 100%;
}

.mat-column-username {
  word-wrap: break-word !important;
  white-space: unset !important;
  flex: 0 0 28% !important;
  width: 28% !important;
  overflow-wrap: break-word;
  word-wrap: break-word;

  word-break: break-word;

  -ms-hyphens: auto;
  -moz-hyphens: auto;
  -webkit-hyphens: auto;
  hyphens: auto;
}

.mat-column-emailid {
  word-wrap: break-word !important;
  white-space: unset !important;
  flex: 0 0 25% !important;
  width: 25% !important;
  overflow-wrap: break-word;
  word-wrap: break-word;

  word-break: break-word;

  -ms-hyphens: auto;
  -moz-hyphens: auto;
  -webkit-hyphens: auto;
  hyphens: auto;
}

.mat-column-contactno {
  word-wrap: break-word !important;
  white-space: unset !important;
  flex: 0 0 17% !important;
  width: 17% !important;
  overflow-wrap: break-word;
  word-wrap: break-word;

  word-break: break-word;

  -ms-hyphens: auto;
  -moz-hyphens: auto;
  -webkit-hyphens: auto;
  hyphens: auto;
}

.mat-column-userimage {
  word-wrap: break-word !important;
  white-space: unset !important;
  flex: 0 0 8% !important;
  width: 8% !important;
  overflow-wrap: break-word;
  word-wrap: break-word;

  word-break: break-word;

  -ms-hyphens: auto;
  -moz-hyphens: auto;
  -webkit-hyphens: auto;
  hyphens: auto;
}

.mat-column-userActivity {
  word-wrap: break-word !important;
  white-space: unset !important;
  flex: 0 0 10% !important;
  width: 10% !important;
  overflow-wrap: break-word;
  word-wrap: break-word;

  word-break: break-word;

  -ms-hyphens: auto;
  -moz-hyphens: auto;
  -webkit-hyphens: auto;
  hyphens: auto;
}

If you're using scss for your styles you can use a mixin to help generate the code. Your styles will quickly get out of hand if you put all the properties every time.

This is a very simple example - really nothing more than a proof of concept, you can extend this with multiple properties and rules as needed.

    @mixin mat-table-columns($columns)
    {
        .mat-column-
        {
            @each $colName, $props in $columns {
    
                $width: map-get($props, 'width');
                
                &#{$colName} 
                {
                    flex: $width;
                    min-width: $width;
    
                    @if map-has-key($props, 'color') 
                    {
                        color: map-get($props, 'color');
                    }
                }  
            }
        }
    }

Then in your component where your table is defined you just do this:

    @include mat-table-columns((
    
        orderid: (width: 6rem, color: gray),
        date: (width: 9rem),
        items: (width: 20rem)
    
    ));

This generates something like this:

    .mat-column-orderid[_ngcontent-c15] {
      flex: 6rem;
      min-width: 6rem;
      color: gray; }
    
    .mat-column-date[_ngcontent-c15] {
      flex: 9rem;
      min-width: 9rem; }

In this version width becomes flex: value; min-width: value.

For your specific example you could add wrap: true or something like that as a new parameter.

As i have implemented, and it is working fine. you just need to add column width using matColumnDef="description"

for example :

<mat-table #table [dataSource]="dataSource" matSortDisableClear>
    <ng-container matColumnDef="productId">
        <mat-header-cell *matHeaderCellDef>product ID</mat-header-cell>
        <mat-cell *matCellDef="let product">{{product.id}}</mat-cell>
    </ng-container>
    <ng-container matColumnDef="productName">
        <mat-header-cell *matHeaderCellDef>Name</mat-header-cell>
        <mat-cell *matCellDef="let product">{{product.name}}</mat-cell>
    </ng-container>
    <ng-container matColumnDef="actions">
        <mat-header-cell *matHeaderCellDef>Actions</mat-header-cell>
        <mat-cell *matCellDef="let product">
            <button (click)="view(product)">
                <mat-icon>visibility</mat-icon>
            </button>
        </mat-cell>
    </ng-container>
    <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
    <mat-row *matRowDef="let row; columns: displayedColumns"></mat-row>
</mat-table>

here matColumnDef is productId, productName and action

now we apply width by matColumnDef

styling

.mat-column-productId {
    flex: 0 0 10%;
}
.mat-column-productName {
    flex: 0 0 50%;
}

and remaining width is equally allocated to other columns

You can easily do this one. In each column you will get a class with the field name prefixed with mat-column, so the class will be like mat-column-yourFieldName. So for that you can set the style like following

.mat-column-yourFieldName {
    flex: none;
    width: 100px;
}

So we can give fixed width for column as per our requirement.

Hope this helps for someone.

You can do it by using below CSS:

table {
  width: 100%;
  table-layout: fixed;
}

th, td {
  overflow: hidden;
  width: 200px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

Here is a StackBlitz Example with Sample Data

Here's an alternative way of tackling the problem:

Instead of trying to "fix it in post" why don't you truncate the description before the table needs to try and fit it into its columns? I did it like this:

<ng-container matColumnDef="description">
   <th mat-header-cell *matHeaderCellDef> {{ 'Parts.description' | translate }} </th>
            <td mat-cell *matCellDef="let element">
                {{(element.description.length > 80) ? ((element.description).slice(0, 80) + '...') : element.description}}
   </td>
</ng-container>

So I first check if the array is bigger than a certain length, if Yes then truncate and add '...' otherwise pass the value as is. This enables us to still benefit from the auto-spacing the table does :)

we can add attribute width directly to th

eg:

<ng-container matColumnDef="position" >
    <th mat-header-cell *matHeaderCellDef width ="20%"> No. </th>
    <td mat-cell *matCellDef="let element"> {{element.position}} </td>
  </ng-container>